Not enough time for a full rate now, but I have a quick suggestion. Even though your team is, quite obviously, meant to be more offensive than defensive, I think a Gastrodon would help with the problems that you mentioned. It's immune to Electric-type attacks, and, if you get one with Storm Drain, then it would gain a +1 SpAttack boost when your Politoed uses Surf. A physically defensive set could handle Fighting-type Pokémon well, even though it doesn't resist those type of moves, and its only weakness - Grass-types - is resisted doubly by two of the other Pokémon on your team. Seeing as Scizor would be more useful, and you said you don't want to replace it, I would recommend replacing Ferrothorn with it.
Then, if Gastrodon is used, you have a small problem with having 3 SpAttack-orientated Pokémon on your team - something that can be easily remedied by switching to a more physically-based Kingdra, or running a mixed set.
You say Ferrothorn can use the rain to help it set up, but Gastrodon would be able to boost its SpAttack while still attacking, which, seeing as hitting as hard as you can is pretty much the Battle Subway's thing, is probably a good thing.
EDIT: Okay, I just noticed your Politoed has Scald instead of Surf. My bad. Surf would be great with Gastrodon, though.