You pretty much named the worst Gambit writers in your first sentence. The only positive I can find for Gambit in X-Men Legacy was him bonding with Xavier for a little while, which is important because of Xavier's status in the X-Men lore. Besides that, he had a couple of good scenes in AoX...but the rest wasn't memorable. Gage was probably the one that had me shaking my head and face-palming in a lot of his Gambit scenes the most. Layman's Gambit, to be honest I dropped it and I don't really remember it, that's how irrelevant it was to me.
I agree with your assessment on Kelly Thompson, I think he's been fine, yes he's watered down, maybe a little too nice and love-struck. It's not quite Nicieza or Claremont Gambit, but I've enjoyed him.