I know I'll change my opinion on all the Pokemon after I get over the initial shock of the wave of new sprites, but for now, I'm going to give my first impressions of a few:
#521 Kenhorou - Definitely not what I would have expected Mamepato's final evo to look. Did it go from being a pigeon to a road runner? The two different forms is odd, too. I'm guessing the Pink Face form is the male (like how male Peacocks have the colorful tail feathers).
#524 Dangoro - Gigaiasu should've been a standalone
#525 Gantoru - Same as above.
#532 Dokkora - VEINS!
#533 Dotekkotsu - Same as above.
#534 Roopushin - Same as above.
#535 Otamaru - Ugly. Ugly. Ugly. Please, take it back.
#536 Gamagaru - Same as above.
#537 Gamageroge - Same as above.
#538 Nageki - Now, I know some Pokemon (like Hariyama) look like they're wearing clothes, but in this case, the Pokemon looks like it literally grabbed a karate suit and slipped it on. At least Hariyama "clothes" appear to be a part of its anatomy.
#539 Dageki - Same as above.
#552 Warubiru - One word: disappointing. Megaruko is one of my favorite Gen V Pokemon, but I can't say the same for this. First, I expected Megaruko to evolve only once. Second, I expected it to remain quadrupedal and not bipedal.
#553 Warubiaru - Same as above.
#559 Zuruggu - Dark/Fighting? That's surprising. Based on its color, I figured it would be Electric-type. I know, that was naive of me.
#569 Dasutodasu - What the...?
#573 - Chillarmy should have been a standalone.
#584 Baibanira - Not needed. Baniricchi would have sufficed.
#589 Shubarugo - Probably one of the most bizarre-looking Pokemon I've ever seen. It looks like it could be a character in "Adventure Time."
#591 Morobareru -Same as above.
#593 Burunkeru - Same as above.
#600 Gigear - After seeing this, Gear would have been better off as a standalone.
#601 Gigigear - Same as above.
#613 Kumashun - ICICLE SNOT! That's too funny.
#621 Kurimugan - Umm... I'm sorry, is this a Pokemon? Really, GF? Really?
#623 Goruggo - Same as above.
#624 Komatana - LOVE IT!
#625 Kirikizan - Same as above.
#627 Washibon - Definitely did not disappoint. I love Wargle's pre-evo.
#629 Baruchai - It looks like it didn't completely hatch from its egg, and the egg looks like a diaper. Interesting design.
#634 Jiheddo - I've dreaded this day; a twin-headed dragon...how cliche.
#649 Genosekuto - My hunch was right: it's hideous.