Lets do a QC sweep.
Use the Boost to Get Through! - I think this is a pretty interesting concept, as while it is something we have somewhat seen before, in the current generation at least, almost all pokemon that have significantly different boosting sets were either too good at them (ie. Mega Lucario) or not really all that impressive in OU (ie. Regular Lucario, Infernape). Looking at how the unpredictability itself effects the viability could be very worthwhile in my opinion. Approved
Burst Mage - I'm not really sure something like this is possible in competitive Pokemon. Draco Meteor and the like have a severe backlash effect, but they are still considered very good moves, and is not really considered to have the cooldown this is looking for. There is not really any mechanic that has a more severe downside, so I'm not really convinced you can get a Pokemon that has that can have this downside without being too weak at the start (short of throwing Simple on a super powered Draco Meteor user). I'd want to see some ideas about how this is actually attainable before we dive into a concept like this.
One Stat Pony - The problem with this concept is that such Pokemon do already exist in OU. As mphallor pointed out, Breloom, Skarmory and Talonflame are all examples of Pokemon with a single great stat and mediocrity everywhere else. What we would be doing with this would really not be anything we couldn't gather by just looking at the existing OU metagame.
Spotlight - The wording here is a bit hard to follow at first, but it seems you are looking for an anti-lead. This big issue here is the lack of real leads for a Pokemon to try and counter. At the same time, it is talking a lot about hazards and stopping them, but then talking about messing with items and abilities. Its hard to really see how this all comes together into one concept. I would advise rewording a lot of what you have here to focus a lot more on either the lead game or the ability/item game. If one is necessary for the other, the process with get to that, but trying to focus on both makes a confusing concept.
The Berserker - Low HP strategies were something that was seen a lot more in some older gens, but you don't see much use of Reversal or Flail nowadays. Priority proliferation is a prime reason for this, but in general, strategies that relied on you being suceptabile to revenge killing are never ideal. I'm not going to say this is not possible, but there is good reason why a lot of Pokemon that could in theory run sets like these do not usually do so, and I think it would be hard to make a Pokemon that relies on these and still make it relevant in OU.
Weatherman - Obviously having coverage moves or whatnot boosted by weather can be used to make a Pokemon ever so slightly appreciate any weather, and taking a Heliolisk approach is possible, where a Pokemon benefits from lots of weatehrs based on abilities, but only one or two for any given set, but beyond that, there is really no way for a Pokemon to be a fan of more than one or two of them without resorting to something like a custom ability, and that is not something we do here anymore. I just can't see this working.
New Typing Tank - Walls and Tanks are good for many reasons, but giving a new typing just to be new will not really confuse or change anything by itself. No typing is invincible, and every one can be countered. This concept seems too generic, and is just asking for a new type for its own sake.
Elephant in the Room - I don't really see Magic Room being viable at all, since, as we have seen with the proliferation of Knock Off, people can adjust to playing without items. Wonder Room on the other hand has a lot more potential. The ability to, in theory, use a single "set up" move to get by dedicated physical/special walls certainly has potential. With that said, I'm not sure this has enough flexibility to make a great project.
Checkmate - Late game play can be a very interesting concept. However, in the current metagame, which Pokemon are great late game varies a lot by team matchup. As ginga said, a wall "checkmate" would just be something that walls the last mon. But this is also true of offense, as an offensive checkmate is just a Pokemon that can clean through the remaining members of your opponents team. I think a concept like this needs to focus more genrically on late game play than specifically looking for a checkmate, since teams are far too varied for a single Pokemon to checkmate teams consistantly.
Dedicated win Condition This is another one looking at more late game stuff, however, while this is more focused, I don't really see a ton of potential here. Almost any Pokemon that makes a good sweeper should be able to win if their counters and checks are removed, so if a Pokemon can do that but is a liability until then, I don't see it getting use over Pokemon that can clean up and also play roles earlier game.
Against the Grain - This is really generic, almost to a fault, in my opinion. There are multiple Pokemon that exist that can take on multiple roles, so this would really need to be more specific if it is to really do something different than what we see all the time.
The Struggle - I like this concept. It takes something that is certainly possible, as shown in many metagames (and even some normal battles), but is never really thought much about, and puts it at the focal point. While I'm not sure how viable it could end up being, I think it would be at least worth taking a closer look at. Approved
Anti-Status - This concept seems to have an idea of taking advantage of status, but it doesn't really seem to want to do it with any of the ways that Pokemon already can do it. The description does not seem to really expand enough on what we actually want to do here, making it hard to base a project off of it.
Stop Hitting Yourself - The issue I have with this concept is that Pokemon like this already exist. You do mention they do, but not to the extent you want for this concept, but I don't really see how to do that much better. I mean unless we just combine them all together I don't see us doing much more than already exists, and even then, I hardly see a Pokemon wanting to utilize them all at once.
Mobius Double Reach-Around - Confusion is a status condition that I don't really think we can make work. It has never seen any use, bar the rise of Swagger early this gen, and even then, that was only used thanks to the Atk Boost, and, often, due to being paired with Foul Play. Despite being around forever, and it even being more accurate than Swagger, nothing ever used Confuse Ray. I just don't believe its benefits can be made worth using without added benefits that don't really exist on moves outside of the now banned Swagger. As for using it on yourself, while evasion boosts from Tangled Feet or what not can be nice, the boost is statistically just not worth it compared to how often it causes negative effects.
The Pacifist... or is he - I don't really see how this is different from other clerics. They all can at least do some damage. If the only criteria for that is that it has to be extreme situations, then either it already exists, or is just a worse version of something that does.
Use the Boost to Get Through! - I think this is a pretty interesting concept, as while it is something we have somewhat seen before, in the current generation at least, almost all pokemon that have significantly different boosting sets were either too good at them (ie. Mega Lucario) or not really all that impressive in OU (ie. Regular Lucario, Infernape). Looking at how the unpredictability itself effects the viability could be very worthwhile in my opinion. Approved
Burst Mage - I'm not really sure something like this is possible in competitive Pokemon. Draco Meteor and the like have a severe backlash effect, but they are still considered very good moves, and is not really considered to have the cooldown this is looking for. There is not really any mechanic that has a more severe downside, so I'm not really convinced you can get a Pokemon that has that can have this downside without being too weak at the start (short of throwing Simple on a super powered Draco Meteor user). I'd want to see some ideas about how this is actually attainable before we dive into a concept like this.
One Stat Pony - The problem with this concept is that such Pokemon do already exist in OU. As mphallor pointed out, Breloom, Skarmory and Talonflame are all examples of Pokemon with a single great stat and mediocrity everywhere else. What we would be doing with this would really not be anything we couldn't gather by just looking at the existing OU metagame.
Spotlight - The wording here is a bit hard to follow at first, but it seems you are looking for an anti-lead. This big issue here is the lack of real leads for a Pokemon to try and counter. At the same time, it is talking a lot about hazards and stopping them, but then talking about messing with items and abilities. Its hard to really see how this all comes together into one concept. I would advise rewording a lot of what you have here to focus a lot more on either the lead game or the ability/item game. If one is necessary for the other, the process with get to that, but trying to focus on both makes a confusing concept.
The Berserker - Low HP strategies were something that was seen a lot more in some older gens, but you don't see much use of Reversal or Flail nowadays. Priority proliferation is a prime reason for this, but in general, strategies that relied on you being suceptabile to revenge killing are never ideal. I'm not going to say this is not possible, but there is good reason why a lot of Pokemon that could in theory run sets like these do not usually do so, and I think it would be hard to make a Pokemon that relies on these and still make it relevant in OU.
Weatherman - Obviously having coverage moves or whatnot boosted by weather can be used to make a Pokemon ever so slightly appreciate any weather, and taking a Heliolisk approach is possible, where a Pokemon benefits from lots of weatehrs based on abilities, but only one or two for any given set, but beyond that, there is really no way for a Pokemon to be a fan of more than one or two of them without resorting to something like a custom ability, and that is not something we do here anymore. I just can't see this working.
New Typing Tank - Walls and Tanks are good for many reasons, but giving a new typing just to be new will not really confuse or change anything by itself. No typing is invincible, and every one can be countered. This concept seems too generic, and is just asking for a new type for its own sake.
Elephant in the Room - I don't really see Magic Room being viable at all, since, as we have seen with the proliferation of Knock Off, people can adjust to playing without items. Wonder Room on the other hand has a lot more potential. The ability to, in theory, use a single "set up" move to get by dedicated physical/special walls certainly has potential. With that said, I'm not sure this has enough flexibility to make a great project.
Checkmate - Late game play can be a very interesting concept. However, in the current metagame, which Pokemon are great late game varies a lot by team matchup. As ginga said, a wall "checkmate" would just be something that walls the last mon. But this is also true of offense, as an offensive checkmate is just a Pokemon that can clean through the remaining members of your opponents team. I think a concept like this needs to focus more genrically on late game play than specifically looking for a checkmate, since teams are far too varied for a single Pokemon to checkmate teams consistantly.
Dedicated win Condition This is another one looking at more late game stuff, however, while this is more focused, I don't really see a ton of potential here. Almost any Pokemon that makes a good sweeper should be able to win if their counters and checks are removed, so if a Pokemon can do that but is a liability until then, I don't see it getting use over Pokemon that can clean up and also play roles earlier game.
Against the Grain - This is really generic, almost to a fault, in my opinion. There are multiple Pokemon that exist that can take on multiple roles, so this would really need to be more specific if it is to really do something different than what we see all the time.
The Struggle - I like this concept. It takes something that is certainly possible, as shown in many metagames (and even some normal battles), but is never really thought much about, and puts it at the focal point. While I'm not sure how viable it could end up being, I think it would be at least worth taking a closer look at. Approved
Anti-Status - This concept seems to have an idea of taking advantage of status, but it doesn't really seem to want to do it with any of the ways that Pokemon already can do it. The description does not seem to really expand enough on what we actually want to do here, making it hard to base a project off of it.
Stop Hitting Yourself - The issue I have with this concept is that Pokemon like this already exist. You do mention they do, but not to the extent you want for this concept, but I don't really see how to do that much better. I mean unless we just combine them all together I don't see us doing much more than already exists, and even then, I hardly see a Pokemon wanting to utilize them all at once.
Mobius Double Reach-Around - Confusion is a status condition that I don't really think we can make work. It has never seen any use, bar the rise of Swagger early this gen, and even then, that was only used thanks to the Atk Boost, and, often, due to being paired with Foul Play. Despite being around forever, and it even being more accurate than Swagger, nothing ever used Confuse Ray. I just don't believe its benefits can be made worth using without added benefits that don't really exist on moves outside of the now banned Swagger. As for using it on yourself, while evasion boosts from Tangled Feet or what not can be nice, the boost is statistically just not worth it compared to how often it causes negative effects.
The Pacifist... or is he - I don't really see how this is different from other clerics. They all can at least do some damage. If the only criteria for that is that it has to be extreme situations, then either it already exists, or is just a worse version of something that does.