Well, Red Faction's Geomod 2.0 took like 6 months to develop, and that's a long time in game development. The buildings are completely physics-based--the dev team had to study up on real-life architecture because their first attempts at buildings collapsed because they were not structurally sound. And the buildings that did exist on the final map were relatively simple buildings, too. I remember maybe 3 stories max for most buildings. If DICE were to have that level of destruction, they'd have to build pretty tall buildings that won't collapse under their own weight. With all of the chaos that happens in a regular match, entire maps would be almost definitely be reduced to rubble by the end of the match, and that would get boring fast. There's very practical reasons for not having such an ultra-realistic destruction engine. Buildings can be built in ways that work best for a multiplayer game, without worrying about making physically stable maps.

While I am perturbed by the transition of destruction form BC2 to current BFs, I can understand why a bit. A game based so heavily off vehicle warfare needs a way to separate infantry from certain death at all times. I hated BF3 because of it's limited destruction, but can forgive BF4 since it's making destruction more tactical. While I will always yearn for the past of leveling an entire map, I can make due with destroying various objects to create new opportunities and limit others.

That's actually a very good question. Volition probably deserves more credit. That being said I haven't played a Red Faction game since Red Faction Guerrilla.

You know what the difference is between buildings in BFBC2 and BF3? In BFBC2 every building is nearly the same. BF3/BF4 have varied buildings. Just like in BF3, the white buildings with the stairs that are the same on every map are really the only things that are fully destructible.