adding--from a TV revenue standpoint, in my opinion. Boise and SDSU are likely candidates based on on-field and on-court success, and location in the case of SDSU. But neither fan-base nor market/brand move the needle to be considered additive.
Not to mention the academic issues with adding two mediocre state schools (which may nuke the whole prospect of either one).
After SDSU and Boise, I see no one else they could add from their fellow G6 conferences.