Writing Hex, for example, felt so much simpler than Go that I really have trouble imagining a programmer trying their hardest to write succinct code for both and ending up with a shorter program for Go than Hex.

I agree that a replication would be helpful, but I expect the ordering of Hex < Dots and Boxes < Go < Checkers to remain the same. If their programs came out different lengths, I suspect if we used each others insights to improve each others code we would still end up with Hex < Dots and Boxes < Go < Checkers.

(If two did switch, I would expect it to be Go and Checkers. I used someone else's carefully thought out ruleset for Go but couldn't fine a similar one for Checkers, so that one's probably got more slack to take out.)