You hit the nail on the head with the 2/3 thumb key bit. That is what was such a game changer for me with the kinesis. all the sudden you have real estate to take a layering approach that you just can't with normal keyboards.

Smart but unproductive is a class. We've all had experiences with those types of engineers. I think startups generally weed them out though. It's hard to survive at a startup without being productive. I probably should have put that as a disclaimer up front.