I'm liking the internal synergy, nobody seems to have mentioned OEs yet, which is probably the first think I would think about. (Keeping it mono). UGs, not so much, although Rage Potioning the upped guys and UGs would be awesome, and probably quite strong too, yet probably balanced.
I wouldn't worry about it too much with UGs, its a duo or splash in any case, and would be unlikely to be more powerful than say, GotP Nightmare.
I agree with the infection comment, and I think two opposing stormbringers would be the coolest thing ever. If the animations were good, then basilisk blood a few times (or even auburn nymph it) and just watch the thunder flow.
Basically, cool card, I like it very much. Thunderstorm was always needing an effective Graveyard card so that it wouldn't just be a +1 card in Airs Bazaar.