It was time someone addressed this, finally.
A thing I found odd and increasingly disappointing is that, despite the "justification" paragraph added to the concept submissions, most of them are lately TOO focused on "what we need in this (CAP?) metagame" than of "which idea we could explore". For example, a lot of people have accused the "Parasite" concept that popped up approximately into every CAP Concept thread of being a bad concept. IMO, it is much better of a concept than some of the past winning concepts. What a concept should promote in fact, if you ask me, is to explore a niche/mechanic/role which is pretty underused/unexplored in the standard metagame. Now, pretty much every concept from CAP4 on have been heading this way (somehow), but while in the past the focus was more on the exploring aspect, lately the "purely competitive" (I will explain this later in this post) aspect began to prevail.
Let me make some examples to prove my point. Examples taken from past polls. The first one is the concept which we transformed into Fidgit, by Magmortified and Aldaron
Concept: Utility-Support Pokemon.
Description: There is a serious lack of Gravity, Rapid Spin, Wish, non Dark weak Trick Room, OU viable Heal Bell / Aromatherapy, Encore, Memento, Non Dark weak Perish Song, Psycho Shift, Safeguard, Magic Coat, Me First, Snatch, Spikes, Toxic Spikes, Tailwind and Haze Pokemon in our lovely Metagame. I don't know what type, what stat distribution or even what kind of Pokemon would effectively use all those, but I want to build a utility Pokemon for the useful yet less used utility moves. If I had to narrow the field a bit, I would emphasize Tailwind, Gravity, non Dark weak Trick Room, Rapid Spin, Wish and Encore. The normal utility moves like Reflect and Light Screen go without saying.
This is actually a good concept (one of the best winners ever, IMO), since it focuses mainly on uncommon, but yet possibly viable stuff with the idea of tailoring a Pokémon towards this job. And actually Fidgit makes fantastic use of its utility arsenal. Most importantly, Fidgit helped us discovering (outside of useless theorymon) that Gravity, Tail Wind, Heal Block and , to a lesser extent, Trick Room, are less viable than standard weather effects despite the boost obtained by courtesy of Persistent.
However, some of the more recent concepts have lost this important focus. Since I can't quote, for the sake of simplicity, almost the entire CAP8 concept poll slate like probably I should, I will call out a pair of examples. The first one has been posted by Zarator - yes, it's me -, the other one by Plus and Magmortified.
Name: Kingdra in the Snow
General Description: A pokémon with good but not excellent sweeping potential which, under Hail conditions, can become definitely a threatening attacking force.
Justification: Let's face it. The only viable way to run hail in OU is through stall. Things like Glaceon, Syclant, Weavile and so on, can't give to said teams the sweeping edge. They are quite unviable in OU (Glaceon), better off sweeping in a non-Hail team which can support them better (Syclant), or do not benefit from hail at all for sweeping purposes aside from breaking Focus Sashes(Weavile).
While a single Pokémon can't all of a sudden completely change a strategy, we all know that Rain Offense would not be all that threatening without Kingdra in the equation (heck, whenever you see a Rain Dance setup you can almost bet that there's a Kingdra waiting in the wings!).
So, I'd say that it would have a positive effect on the metagame. It would give Hail a chance to stray a bit from stall by putting it on the offensive, and could give to a low-used weather effect a tool to shine a bit in the OU environment.
Explanation: Of course, Hail itself help little in the way of offense, aside from the damage itself and Blizzard accuracy boost. So, This Pokémon will need:
1) A proper typing. Ice/(Rock resistant type) is the most probable, but going for something non-Ice is a possibility.
2) A good ability. Probably a custom ability, since the current Hail-related abilities do not help sweeping directly. This ability would also nullify Hail damage in case CAP8 does not turn to be an Ice Pokémon (like Cacturne's case)
Name: The Pivot Point
General Description:This Pokemon would help add a new element to making offensive teams. Instead of going full glass cannon or bulky offense, it would be possible to structure a team around this Pokemon and use it strategically to keep the momentum of the battle going in your favor.
Justification: This Pokemon wouldn't be a wall. Nor would it encourage walls. This would take some hits and allow your offensive team a base to build itself around. Essentially the glue that holds everything together while your other Pokemon do their jobs. Ideally, it would also be able to dish out some damage, so as to hold momentum. It would definitely give a positive effect on the metagame.
Explanation: It will make the other Pokemon's job easier through support, yet it will still be able to keep itself on the offense with decent enough attacks. But its primary function would be to - through typing, stats, or combination of both, be the glue of the team that holds everything together to your advantage.
What's bad about those two concepts, Zarator? Probably this is the question you are gonna ask me. Let me answer. The first one, my own concept, is bad since it is completely "wrong". Why? Because Hail, like Sandstorm, is built to stall. Not because of the Pokémon which benefit of the ability, but because of the weather themselves. ok, Hail may have that 100% Blizzard, but that's all about it. While the "Kingdra in the sun" which have been always used as a paragon for a good concept in the OPs can work because sunshine is an offensive weather no matter how you look at it, "Kingdra in the Hail" is just as good as "Trick Room staller". To word it better, it sucks. Why I have posted it, I don't know. We all make mistakes, after all.
"Pivot Point", on the other side, is not very good of a concept because, well, pivot points already exist. Porygon2, for example, is a good pivot point. It isn't a wall (since it can counter only very specific, high level threats and not an entire side of the spectrum or almost both like true walls), and it does not encourage walls (How many times have you seen Porygon2 on a well built stall team? Yes, none). It is the glue (the analysis itself calls Pory this way) that hold together an offensive team allowing it not to be swept by some prominent threats like Salamence, Jolteon, Gyarados and Heatran. While it is certainly possible to build a better "Pivot Point" (P2 is not even OU, after all), you can see it is not as innovative as the "Pure Utility". Same thing goes also for Beej "Ultimate Scout" which produced Kitsunoh. Does OU really lacks viable scouts?
To sum this up, I think we should stop thinking CAPs like "This is what my team needs" but, rather, "This is what the metagame lacks". Otherwise, there's nothing we can learn from such a research.