Wait until you see the regional dex. X/Y had over 450 Poke'mon in the game (Not counting Megas). There's a lot of Poke'mon that I'm sure nobody will miss like Zigazoon, a lot of UU Poke's, and Legendaries. Then there's all the Pokemon that fill the same role as Poke'mon from previous gens. Like Conkledurr and Machamp.
Also, there's no reason why they can't slowly patch the rest in over a year.