Farfetched, Delibird, Dunsparce, Shuckle, Corsala, Spinda, Torkoal, Chatot, Maractus, Stunfisk, Jynx, Heliosk, and maybe a few others have too basic designs and/or have a lot more potential
Kangaskan needs a pre-evo, although they probably won't give it one, as well as Lapras, Tropius, Carnivine, Audino, Druddigon, Bouffalant, Heatmor and Durant,
Luvdisc needs to evolve in Alomomola
Zangoose and Seviper so that they can change types when they evolve to each have a typing that is strong against the other and one weak against the other
All Electric Rodents starting in generation three need at least one evolution, and Plusle and Minum could have some thing where they evolve at level 15 or 20 if they're counterpart is in the party and Dedenne needs to evolve into Raichu
Dragonair should get a split evoltion so it can evolve into something sleek, graceful, and snake-like instead of Dragonite
And of course Eevee needs more Eeveelutions like flying, bug, poison, rock, dragon, steel, ect.