Snaquaza
KACAW
Well, I'll post my thoughts on Arena Trap. I'm currently actually not sure whether I want it banned or not, but I'd love to see a suspect, since it's definitely threatening.
Anyway, to start of. I actually think Final Gambit on high HP Pokemon is the most threatening. It doesn't have as much options as running an actual set, but it's great at removing a certain Pokemon. The problem is obviously the high opportunity cost here, since you basically run one Pokemon which you can't use besides removing one Pokemon. I admit that other Arena Trappers are a threat, with Earthquake, Stone Edge and Sucker Punch, but they are usually flawed in some way. They may be really annoying for some teams, but they've still been fairly mediocre to me, but that's not the point.
As Lcass4919 and others said, the problem is that Blissey (or whatever Pokemon you want, really) can easily destroy any Pokemon you want, as long as it's not a Ghost type / Flying type / Levitate Pokemon. This means that it can remove nearly all Pokemon. It's true that quick Pokemon can stop them. This can be a huge problem for stall and balance, though it's not as good against offensive since they have a lot of priority and very quick Pokemon. And even if they lose a Pokemon, they'll probably have more Pokemon that can at least prepare a sweep. For balance and stall it is more annoying, since they may rely on a certain Pokemon to fulfill a certain role and wall something of the opponent, which is something opposing teams with Blissey can easily take advantage of.
Don't be fooled though. A team should never be swept solely because one Pokemon was removed. Sure, it might be way harder to defend since a critical support Pokemon or wall was removed, but it should not lead to an immediate miss. The opponent will have a way easier time wearing you down probably, and eventually beating you, but it should not be the case that he can switch in a Pokemon and you have no way to beat it. Otherwise you will be beat by any lure, not only by Final Gambit Blissey. (By this, I'm not saying Lures are the same as FG Blissey, but they have the potential to surprise KO something as well. The main difference is that you need to predict and everything for a lure, and just switch in and KO with Blissey.) But if your team is outright swept if a certain Pokemon is KO'd, you'll never win if they either managed to wear that one down, or lured it in and KO'd it. This means you should always have a soft check left. (Something that can't switch in, but can one on one.)
I also want to say that comparing it to Gothitelle is not helping. I don't think Gothitelle is OP, even though it gets tools to break Stall. It's not really strong and is weak to all forms of damage. Stall is not even passive here, and as Adrian Marin has said multiple times. You should not have a passive Stall team here, or it'll just fodder to one of the many strong sets in the metagame. With the insane offensive threats we have, it's a must to have a somewhat threatening team so Offense can't just keep firing strong hits at it. Gothitelle can trick you a Scarf, and while this may cripple a Pokemon, it shouldn't outright make it unusable, since it's still able to use its moves. (Unless it used a status move on Gothitelle which is a bad idea.) This means that the problem must be the Pokemon that inherit Arena Trap, which have, as previously stated, sparse movepools. The best tool Pokemon can use to be actually "uncompetitive" would be Final Gambit, and the others are annoying, but usually able to be handled. I'm not sure whether they're OP, as I've personally not seen Arena Trap destroy things per se, but I can imagine Final Gambit being annoying, while normal Trapping has been kinda mediocre to me. It'd be good if anyone posts some replays that actually proof a point. This does not include Gothitelle tricking a Scarf onto something which had Shed Shell so WAS able to switch out. It'd also be good to see someone using it, and him giving his opinion on the matter. Arena Trap beating you once, isn't as much as an argument as someone who uses it saying it's too easy to beat common Inheritance threats with this ability.
What's needed to convince me is just whether Arena Trap is so good that it can dismantle cores in teams well enough for other Pokemon in the team and that it's not a waste of a moveslot most of the time, or that you'd be better off running something else. For normal Arena Trap sets, you have to convince me how they actually beat common sets, without being dead weight most of the games. I do agree that they don't have to work against all teams, but they shouldn't be near gimmicks. As I've heard many people say Final Gambit was a gimmick and was not worth it. The fact that I don't want to ban too much means that I'll try to be conservative, but if it's really an issue, I won't hesitate to ban it!
Anyway, to start of. I actually think Final Gambit on high HP Pokemon is the most threatening. It doesn't have as much options as running an actual set, but it's great at removing a certain Pokemon. The problem is obviously the high opportunity cost here, since you basically run one Pokemon which you can't use besides removing one Pokemon. I admit that other Arena Trappers are a threat, with Earthquake, Stone Edge and Sucker Punch, but they are usually flawed in some way. They may be really annoying for some teams, but they've still been fairly mediocre to me, but that's not the point.
As Lcass4919 and others said, the problem is that Blissey (or whatever Pokemon you want, really) can easily destroy any Pokemon you want, as long as it's not a Ghost type / Flying type / Levitate Pokemon. This means that it can remove nearly all Pokemon. It's true that quick Pokemon can stop them. This can be a huge problem for stall and balance, though it's not as good against offensive since they have a lot of priority and very quick Pokemon. And even if they lose a Pokemon, they'll probably have more Pokemon that can at least prepare a sweep. For balance and stall it is more annoying, since they may rely on a certain Pokemon to fulfill a certain role and wall something of the opponent, which is something opposing teams with Blissey can easily take advantage of.
Don't be fooled though. A team should never be swept solely because one Pokemon was removed. Sure, it might be way harder to defend since a critical support Pokemon or wall was removed, but it should not lead to an immediate miss. The opponent will have a way easier time wearing you down probably, and eventually beating you, but it should not be the case that he can switch in a Pokemon and you have no way to beat it. Otherwise you will be beat by any lure, not only by Final Gambit Blissey. (By this, I'm not saying Lures are the same as FG Blissey, but they have the potential to surprise KO something as well. The main difference is that you need to predict and everything for a lure, and just switch in and KO with Blissey.) But if your team is outright swept if a certain Pokemon is KO'd, you'll never win if they either managed to wear that one down, or lured it in and KO'd it. This means you should always have a soft check left. (Something that can't switch in, but can one on one.)
I also want to say that comparing it to Gothitelle is not helping. I don't think Gothitelle is OP, even though it gets tools to break Stall. It's not really strong and is weak to all forms of damage. Stall is not even passive here, and as Adrian Marin has said multiple times. You should not have a passive Stall team here, or it'll just fodder to one of the many strong sets in the metagame. With the insane offensive threats we have, it's a must to have a somewhat threatening team so Offense can't just keep firing strong hits at it. Gothitelle can trick you a Scarf, and while this may cripple a Pokemon, it shouldn't outright make it unusable, since it's still able to use its moves. (Unless it used a status move on Gothitelle which is a bad idea.) This means that the problem must be the Pokemon that inherit Arena Trap, which have, as previously stated, sparse movepools. The best tool Pokemon can use to be actually "uncompetitive" would be Final Gambit, and the others are annoying, but usually able to be handled. I'm not sure whether they're OP, as I've personally not seen Arena Trap destroy things per se, but I can imagine Final Gambit being annoying, while normal Trapping has been kinda mediocre to me. It'd be good if anyone posts some replays that actually proof a point. This does not include Gothitelle tricking a Scarf onto something which had Shed Shell so WAS able to switch out. It'd also be good to see someone using it, and him giving his opinion on the matter. Arena Trap beating you once, isn't as much as an argument as someone who uses it saying it's too easy to beat common Inheritance threats with this ability.
What's needed to convince me is just whether Arena Trap is so good that it can dismantle cores in teams well enough for other Pokemon in the team and that it's not a waste of a moveslot most of the time, or that you'd be better off running something else. For normal Arena Trap sets, you have to convince me how they actually beat common sets, without being dead weight most of the games. I do agree that they don't have to work against all teams, but they shouldn't be near gimmicks. As I've heard many people say Final Gambit was a gimmick and was not worth it. The fact that I don't want to ban too much means that I'll try to be conservative, but if it's really an issue, I won't hesitate to ban it!