Based on one of my in-progress games, I hope they add "qfmebxi" posthaste.
Any two-letter word with a C or V.
QUO still isn't a word right? It really should be. (Side note: I spent months on WWF waiting to get the appropriate set up so I could try to play DISDAM, just so I could make a Golden Girls joke. It was totally worth the effort.) (No, probably not.) (But I laughed.)
Kwyjibo and Cromulent should certainly be in there.