Politoed is good but I don't know why you have 4 Speed EV's? I mean it can take a hit and it's not going to outspeed anyone soon. Go for SpD EV's. The moves and all are good :D
Thunderus-T, while good at sweeping, lacks some base speed even with Timid. Agility might suit you better, but not that I don't think Nasty Plot is bad or anything. Also, I prefer Focus Blast over Grass Knot, it covers more and Thunder covers Water anyway. Anyway, I think a Scarf or Agility will be better, but it's your choice ;)
While good, Focus Sash is useless, 80% of the time on your team. Since you don't have a spinner, and the growing use of SR and Spikes and Toxic Spikes, Focus Sash goes bye-bye. Have Life Orb or White Herb. Also, I think you're mixing two different roles into one. Spinner and Shell Smasher doesn't go well. Either have one, or the other. So like I said, if you want to go with Spinner, it's Defense comes into play. You can also use it as a POke to lay out Spikes.
Why go with Timid when you have Scarf? That makes no sense, plus Modest gives it enough juice to hit extra hard. But, Tornadus-T is a great Life Orb abuser, the Regenerator heals back any damage done to it. Also, Specs is an option. Just saying.
No comment, it's good as it is :D
Why Pursuit. I know it gets Technician boost, but something like Superpower hits extremely hard, even to resist, after some Swords Dance's. And, Life Orb is an option.
Nice team overall, just know that you don't have a lot of walls. But you already know that ;) Good team, and good luck with it.