I'd say..
-Instead of random new pokemon that are pretty much replicants of old ones (pidgey=starly=etc) why not have new Pre-/Post-Evolutions for the old generation pokemon that don't have one (e.g. Farfetch'd, Kangaskhan, Pinsir, Tauros, Lapras, etc)
-Eevee's for the rest of the types...