I think its been discussed to death - IMPOSSIBLE
it pushes the engine to its limit and changes gameplay drastically.. sure in the Ardenne I would like foxholes etc, etc - But Natty once said, its about playing with the existing environment rather than creating your own.
Its not only a new architecture being employed, but a new philosohpy that has currently not been considered for FH2 gameplay, like destructible everytihng...
FH2 HAS fixed foxholes already.. or at least craters, more so than FH1... I think those are cool for the most part
Besides, it should take half a day to dig a proper foxhole... How much of the battle should be spent digging temporary cover?