It started this last week. Randomly when i use thunderstorm the game wont react. No visual, the enemies just stand there, and i can't use any interface settings. Nothing happens for about ten seconds. Then the game reacts to everything I pushed usually killing the mob i attacked. This time the game crashed. Although I can move it's almost like the game freezes then corrects its self.
This isn't necessarily a problem with T-Storm--it's likely more of a connection issue somewhere. You might want to give your ISP a ringy and ask them to run some remote tests to see if there isn't a problem in your location or if there are regional issues they know about.
BTW, one of my toons is an M/D, and I've had no problems using T-Storm in the Goblin Games.