2 fingersman:
*Force field, maybe not bad idea, i dunno, i think that could work out...
*Tanks /w machineguns, no way, that's just dumb, especialy if those guns are close range =] and if they work only on siege mode, thats not logical dont u think? I think tanks are too powerful already.
*New vehicle, maybe, but I think it's enough of those vehicles except ATM, that would be awesom and original unit in BW, I'd love to see something like it...
*CC detonation is the best idea of yours, man, that's a good one, lets say someone rushes with lings or zealots and attacks your CC, you blow up your base and kill all lings or zealots around the CC, this would bring some new tacticts and hell a lot of laugh =], It should work like nuclear bomb, just way less damage. Or maybe all terran mechanical units and buildings should do some damage after destroying, that would help them to stop toss and zerg rushes i think
and more ppl would use range units agains terran probably =]