I'm thinking that you are missing a good bit of special Bulk. Ferro is your main defense in that Regard, and if it follows on from TTar it is Boosted further, but if that gets taken out, you lack a lot of sp Defense. Furthermore, as said previously, Walls like Rotom-W present a major threat with Will o Wisp. That said, consider investing in Sylveon or Gardevoir. Both can act as support, get access to good healing moves, ideally heal bell and also have a good amount of specially offensive options which would round out your Team. Personally, i'd swap Bannette for one of these 2 options,but hey, your choice,