I really dislike when they drastically change the concept with cross gen evos. Its not ALWAYS bad (Basculegion pretty strongly shifts from literally my mom's pirhanna to channeling the lifeforce of the death of a school of fish, and its badass for it), or hyper focus on one element. The results are shoddy.
Rhyperior, for example, leans super fucking heavily into the drill part of Rhydon, turning it into a construction worker for some reason. Rhydon was supposed to be a cool Kaiju with a drill, not explicitly meant to be a jobmon. It drastically shifts the appeal of the Pokemon in question.
Lickilicki's another example of hyper focusing. Lickitung is a salamander tongue monster, and instead of keeping that varied, semi-natural quality, they said "fuck it hes an obese gourmand". It's this really one-track-minded way of designing, uninteresting, and hurts the appeal of the design. It's no longer a weird monster, its a silly joke creature.
Magnezone turns from a multiplying magnetic robot organism, which is a cool, cold, almost mathematical/kaleidoscopic/fractal concept, into a fuckin UFO. I dont hate Magnezone, but its so much more stereotypical than Magneton, and way less cool as a result.
It doesn't help that these designs are just pretty ugly in general too. Rhyperior is at least monstrous and strong, but its also obese and unwieldy. Something like Mismagius shifts tracks pretty fucking hard too (Nukekubi yokai to a generic witch), but it at least looks pleasant.
