This was actually my point, it had nothing to do with my personal opinion. I'm not "blinded by nostalgia" as people like to point out to people who are critical.
But here are some of the things the newer designers do that stand out to me.
-Very basic shapes form the monsters.
-Minimal details in muscular structure on more formed monsters.
-Odd or abstract color combinations.
-Being very loosely based on an animal with some designs while being heavily based on animals in other situations within the same gen - which is inconsistent in design.
- Relying heavily on a concept itself rather than implementing it into the monster. As in the monster precedes the concept, it should be vice versa really.
I don't think these are tropes are predominant exclusively in later generations (with the exception of color scheme, which the original designers nailed for the most part save for a few oddballs like Aerodactyl and Typhlosion). I see some of the criticisms you make in pokemon like Helioptile (sphere-head) and Druddigon (abominable Salmon, Navy and white color scheme,) but I think plenty of older pokemon are also guilty of some of these things. Some offenders I find listed in order of your points
-Jigglypuff line, Seel, Doduo, Magnemite line, Qwilfish, Sentret, Chinchou
- Hitmon family, (The criticism about muscular detail is somewhat confusing. I couldn't tell if you meant actual muscle or muscular proportions)
-Ariados, Hoppip line,, Gligar (in addition to previously mentioned color goofs)
- Noctowl vs.Fearow, goldeen/Seaking vs.Kabuto/Kabutops, Farfetch'd vs. Porygon, Quagsire vs. Octillery
- Venusaur, Beedrill, Granbull, Seaking, Ursaring (this the other one I've had an issue with. You're taking issue with tacked on features, yes?)
The consistency thing is the one I take the most issue with, because from the start pokemon has emphasized variety over cohesiveness. In every generation there's down to earth monsters, there's mythical creatures, "what the fuck am I looking at" monsters, sentient objects, sentient plants, cyborgs, genetically modified monsters, malicious spirits, creepy-ass anthropomorphs. Pokemon are always inconsistent as a group because the developers aim for variety first and foremost. There's a pokemon out there for everyone, and that wouldn't be the case if they stuck to a fairly limited design ethos that held to strict principles. Not every pokemon is good, but there's enough for someone to get attached to and enjoy, As somebody who usually likes 1/3 of the designs from any given generation at best, I'd say that's the most important part.