I don't necessarily dislike Chesnaught's design, but I wish he'd be a bit bulkier so he could fill up that empty space inside his own shell. In general he just looks so plain. If you leave out that shell he's got nothing that would make you think he's part of Chespin's evolution line. Same for Dephox, plain as bread.
Except for Greninja these evolutions are just okay, there is nothing special/innovative/creative about them that some people are claiming.
It's quite funny, Froakie's first evolution was the plainest one. Braixen was the most creative and surprising one, due to her Stick and her bipedality. Quilladin was the most mysterious one, since nobody knew what would happen at the end.
At the end Greninja really surprised everyone with his tongue scarf (even though it is still kinda weird to me), especially his dark typing, since a lot expected fighting (which does make more sense, designwise).
Dephox is in my eyes the plainest starter evolution ever seen. A fire fox in a red robe (this is how much it takes to describe Dephox).
Chesnaught should've been the one with the biggest surprise factor and he probably was to a big part of the community, but for me it was obvious that he'd have a shell with spikes, I just hoped it would look better. I mean, he doesn't even fit into his own shell, like it really was stolen from Bowser. And his fighting type really is a mystery to me. I feel like if it weren't for Dephox' psychic type, the other two would've gotten a different one.
Don't get me wrong, I'm not really hatin' on these designs, but imo Ken can do better than these three. Personally, Pokemon should look at the end of their evolution line like "adults", but this time they seem (at least for me) like teenagers, like they could evolve one more time. Probably they'll be able to (mega-)evolve in another edition.
For the people saying some had too high expectations, I think they may not had too high expectations, just different or maybe used to "better" evos.
But at the end it does come down to own preferences and taste.
And hello to the Pokebeach community