Your team seems fine, but I can see it struggling against set-up sweepers and strong Fighting-Type wallbreakers.
I personally don't love Dragon Dance + Superpower, it's kind of a nombo. Also from experience, Tentacruel ends up taking way more physical attacks than special, I'd go Bold with 116 Speed - 252 HP, and the rest on Def.
I'd consider Ice Beam or Haze instead of Sludge Bomb too.
I love Rotom moveset, I think those are the 4 best moves It can have. Blissey's set is also great (consider giving her Teleport maybe, it's great to never lose iniatitive, which you will need).
Anyway, just jump into some PvP matches and you will quickly see what's to improve. Good luck! π