I too lust after some good factory romps.
I'm a little disapointed in what I've heard about factories so far. no vehicles inside, not as 'flash' graphically as I had hoped. But, hey you can't expect everything and CM:BB allready delivers so much.
I hope you can place guns/mines inside bldgs. I don't think you can 'extra fortify' a bldg
-sewer movement is in
-havn't heard nuttin about cellers so, I think there are none.
-I think keyholing is out (holes in walls) last I heard it is an engine limitation.
-grenades, molotov's are upto scenario designer.
-hand 2 hand fighting (blades) was in CM:BO
-squad lvl smoke is out AFAIK as most people think it was not used much/was ineffectual when used
there are trenches