Well. I think there are two reason that there won't be BF3 like destructions (though I would love this) in Arma 3. Frist: The World is to big and already know suffering under high Perfomance Problems in Multiplayer. Second: The Engine is not built for such Destructions.
But it would be an awesome feeling and creating much more atmosphere. When you running through a BF 3 street with all this smoke and broken parts of a building flying around you, it just feels like wow.
Also I would welcome some more Close Quarter Combats in Arma 3 and some smaller areas, but I have to admit that I am new to the Arma series and this does not seem to be the way arma works. (I would say, Arma 3 is definitly a game for more grown up people, wide more complex and nearer to a simulation)
Theres another aspect that I don't like, and I saw some pages before (the video where the house is destroyed by that demolation ball) how it should be: when a building crashes in games, most of the demolated parts disappear or a solid as a ground. But it would be much cooler if the ground would be fexible or dynamical. (Remember The Snow in Assassins Creed 3?) All in all, playing Arma 3 I have the feeling that there is almost perfect Animation work, but the character does not fuse with the world. Its like you took a womans Foto and photoshop her to another foto, where she does not really fit in. (blabla, i am so bad in explaining things xD)
Really excited what this game will be in the end (for me personally, there should be a mixed shooter out of battlefield 3 and arma 3 with a cover and lean/blindfire system as smk brought it to arma 2; anyone here who wants to make me that game? :D)