its a yes and NO they could do something like that but i think its gonna lag as hell.........and it would be a lot of work
when they divide the map into really small pieces and make them all destructable
but that is a hell of work...one m² would have to be made from like 300 pieces and all would be needed to be skinned...and it sure will lag.....but if u fire a kamehame ha in a random direction that would somehow look like in the picture above. but the area will be just removed...no rocks will be lifted up or something. and they would have to add a fly by damage. that would be a good idea anyway! because now the beam only damages what gets hit by it....in show they also got damaged by beams which flew by!
dont know really how bad it would lag........maybe gonna do a map like that later to see how and if ^^
other possibility is to rewrite the engine(sure not gonna happen) or maybe they find some other way......would nice but i dont bet on that....
in budkai there is a lot destroyable indead.....but everytime only the same....there is a rock which gets splitted there is a ground where the hole is prepared....its not like fire your beam and there is exactly that part destroyed