Hmm... I think there's a few that would work better with a mid-stage, like Shroomish to Breloom or Flittle to Espathra, the change in the evolution is just WAY too much.
You're dead right about Golem, it's such a strange turn from where the line was going before then, from rock with arms to turtle thing.
I'd add Gengar into that too, he's just so stubby and dull compared to the genuinely creepy Haunter.
In terms of downgrades, a lot of the Gen 4 additions I think aren't great, like Rhyperior or Magmortar, they feel way too overdesigned and cluttered compared to the originals.
One of those Gen 4 evolutions is actually my least favorite Mon of all of them, I offer 1 imagination dollar to anyone who can guess what it is
One last thing, are you sure about the Dragonair/Dragonite thing?
Dragonite has higher base speed according to Bulbapedia
