Can we please stop emphatizing defensive type synergy in a tier where it was thrown out of the window the instant Primals and MegaMence became a thing? Ubers is all about offensive pressuring and speedcreeping right now and only a fool would rely on resistances to check the current offensive threats instead of sheer power and/or bulk. This is why stall is almost unviable, Lugia is the #1 wall (despite its horrid defensive type), Groundceus is the #1 PDon check despite not resisting its STABs, steel types such as Mega Scizor and Ferrothorn are no longer good blanket checks to most of the metagame and so on. The fact Arceus-Ice is considered a better Mega Mence check than Arceus-Electric speaks volumes of how meaningless resistances are when you're weak to even one coverage move in a tier where 150+ offensive stats are the norm.
Been said that, dropping the likes of Kyurem-W and Palkia because they don't offer meaningful defensive synergy is nonsense. They're not meant to take hits, they're meant to nuke the hell out of the opposing team with their high-powered STABs and coverage. Palkia has a better speed tier, movepool and it's not weak to rocks making it better against offensive threats, while Kyu-W has more power, a great ability and better STABs, making it the better wallbreaker of the two. Neither of them deserves to drop anywhere close to the C ranks and once again I suggest to move them higher, at least no lower than B+.
On a related note, Aegislash needs to drop. What does it do besides checking Xerneas? And why would one need Aegislash for that role when P.Don exists? It's typing isn't good at all in ubers since it's weak to both of P.Don's STABs (and by extension, weak to the one type P.Don is, which is everywhere in ubers), dark, ghost and doesn't resist water and electric. Pretty much everything in the S- and A- ranks use these types as either STAB or coverage. On top of that KS is an extremely risky move in ubers since contact moves are less common than OU and giving the opponent a single turn to set up can spell disaster. It is certainly not on the same level as regular Groudon, hell it's not even as good as a lot of stuff in B-. C+ or even C is where Aegi should be.
Been said that, dropping the likes of Kyurem-W and Palkia because they don't offer meaningful defensive synergy is nonsense. They're not meant to take hits, they're meant to nuke the hell out of the opposing team with their high-powered STABs and coverage. Palkia has a better speed tier, movepool and it's not weak to rocks making it better against offensive threats, while Kyu-W has more power, a great ability and better STABs, making it the better wallbreaker of the two. Neither of them deserves to drop anywhere close to the C ranks and once again I suggest to move them higher, at least no lower than B+.
On a related note, Aegislash needs to drop. What does it do besides checking Xerneas? And why would one need Aegislash for that role when P.Don exists? It's typing isn't good at all in ubers since it's weak to both of P.Don's STABs (and by extension, weak to the one type P.Don is, which is everywhere in ubers), dark, ghost and doesn't resist water and electric. Pretty much everything in the S- and A- ranks use these types as either STAB or coverage. On top of that KS is an extremely risky move in ubers since contact moves are less common than OU and giving the opponent a single turn to set up can spell disaster. It is certainly not on the same level as regular Groudon, hell it's not even as good as a lot of stuff in B-. C+ or even C is where Aegi should be.