Comment by Fwirt

Yep, those are the ones! There's also the oddity of the [[ and ]] motions. In the POSIX standard, those are the only two-character motions. I was using a state-machine to implement motion commands, and that single command threw a wrench in the works. Of course, vim took two character commands and ran with it, so in vim [ can be followed by a whole host of characters that all do different things. Since g was not mapped in vi they also did the same thing there.