The pokemons I think really really need to evolve:
Farfetch'd, that poor thing gets much too few screentime and really need to evolve into something mindblowing awesome! Many cool things can be done with its evolution!
Both Tauros and Miltank could have a pre-evolution!
Pinsir should also get a Pre-evolution.
Qwilfish could also have a very neat evolution! The poor thing now looks kinda boring and alone.
Corsola should get a evolution based on brain coral or about reefs.
Stantler would be cool if it got a cool upgrade, but I like it already.
Smeargle is the weakest stand-alone pokemon of all, it should get an artist pokemon evolution, tha would be soooo cool.
Both Sableye and Mawile are cool, but they can become much cooler with bigger evolutions.
Spinda could get some Pandabear evolution.
Kecleon Evolution would be awesome as well, maybe some Normal/Dragon type?
Castform becoming some weather-lord would be awesome.
Chatot, that poor thing needs to evolve into a beautiful operah singer parrot.
Emolga and Pachirisu: Please give these poor little things a cool big upgrade!
Durant would be cool if it evolved into an metal ant-warrior and then into a metal ant-queen so that it can protect itself against Heatmor who doesn't get an evolution because he's cool enough already.
I hate no pokemon as much as I hate Delibird, so I hope he never gets a evolution and that this christmas pokemon is forgotten forever, never catch that thing.
Also Dragonair and Flaaffy should both get a second upgrade much like Politoed was to Poliwrath, I really, REALLY dislike both Dragonite and Ampharos, they should be replaced for a dragonair-like evolution and a sheep-like evolution, a ram maybe.
Btw, I really hate the evolutions of Tangela, Blissey and Lickitung, those are just horrid!