think of it like this: granted that they add the ability to "aim" with a B attack, but since some characters can already influence the angle of their attack (take samus' side smash, its angle-able, or zelda's side b) they would probably only give it to some or most (or all) of the characters who couldn't already do it, gets?
oh! and as for fr0st2k, they didn't say anything about reprogramming/remaking/changing move sets yet, because it can be clearly seen in the trailers that the four (mario, link, kirby, and pikachu) are still able to use their melee B attacks, i could still see link doing his up+b, and pikachu doing his Down+b. but then again, it IS just a trailer, and trailers mean that it is most likely in its experimental phases, so there IS a possibility that they will swap/change/whatever their move sets. however, it is MERELY a POSSIBILITY. ok?
(and i don't mean to sound offensive or anything, it's just, next time you should think deeply about what you should say, ok?)