I just wanted to raise a few points from a non-admin PoV.

People play for their own enjoyment, not as a service to others. If someone doesn't enjoy defending, then surely they are entitled to not do it. Anyone is free to leave the game whenever they please. If you start mandating that people are forced to play, then it's a very slippery precedent you are setting.
I share your frustrations that it can kill a good game, though - don't get me wrong!
With regards to balance, could we have a trial period where titan team fix is disabled for assault? If it becomes say, 7v10, I'm pretty sure most of the time someone would just switch if asked, rather than have the random choice made for them by the TB. This way the correct player can switch team rather than the guy with -40 net.
RE: Bans in general, you should all get your heads together and pen down what deserves what. Especially cross server. I see different admins giving vastly varying sentences, and it's only going to cause frustration when someone gets a 7 day for X, then someone else only gets a session ban for X.
Ending on a positive note, I'm sure I speak for 99% of the players when I say we're all thankful for the effort you guys put in.