@BAD
in competitive fighting games, it is important to have a golden standard to base characters off of. we know for a fact that melee falco, fox, marth, jiggs, etc are working, tested and true designs of characters within the melee fighting game genre. their playstyles have stood the test of time of almost (or more?) 6 years. this gives us a a pretty good idea of who's playstyles work, and who's don't. think of it this way - falco/fox/marth are essentially the ken/ryu/chun of street fighter (not in that order or comparable), yes those characters have been altered a bit every iteration, yes they have moved around on their tierlists in different games, but their base gameplay is still there- can you imagine ryu without his hadouken? chunli without her kicks? that's the same as falco with no shine. with ryu/ken/chun/zangief as known functioning playstyles/movesets, the devs at capcom have a better way to base their new characters and gameplay mechanics around since they have a nice bundle of characters that function within the little world they've created.
if we kept falco/fox/marth the way they are in brawl and just slapped on melee mechanics, not only would the metagame of those characters have to be completely relearned, but the metagame of melee itself would be gone. since PM is going to be very faithful to melee's mechanics and core gameplay, there's no reason for us to abandon what falco,fox,marth,jiggs,etc players have learned over the past 6 years.