I was looking over my spreadsheet of characters and out of the 200 or so characters I have, a few ATs I simply do not enjoy playing. I've tried all ATs at one point since 2004 but these are the ones I currently steer clear of for reasons ranging from how they play to a complete dislike of the class as a whole:
Controller
Dominator
Mastermind
HEATs
VEATs
What do you avoid playing and why?
Well, first I am saying that a clean install works fine. Second, I am saying look into your registry or the Mids file structures for any files or entries you may have missed. Or just throw your hands in the air and give up.
If you let Belladonna escape and side with the Resistance you will not be able to do the Loyalist Power arcs (Dr. Hetzfeld, Bobcat, Neuron) until you do another morality mission and select the Loyalist option.
I still take Combat Jumping at 6, travel power at 14, and Hasten (if used) at 22. It is pretty much my build template for almost all builds. I do find the added attacks at lower levels a plus when playing a tank.