haven't heard that one, i saw it was to keep people from jumping and going prone in mid air to become a smaller target.
Sounds bogus if a dev gave that excuse: make foot contact to ground a prerequisite to going prone.
Prone making snipers too hard to spot... Not really, not when you've got such visible tracers and damage direction indicator. Even less if you've got team mates on the radio.
BF3 - Not much to do but wait and see. It's seriously easy to tweak the last few bits that separate BC2 from being as good as people can reasonably wish it were.
I don't mind lack of run strafe or prone. IMHO the really ugly stuff is all the bugs, weapon balance all over the place, completely wrong ballistics (tracer doesn't even match bullet), inaccurate gun sights (!...), treadmill effect half the time you move up an incline, dysfunctional friends list... A big list that I don't recall anymore.