I don't think you can say we'll "all" watch. I haven't watched a single CFP championship game, and I only caught one or two of the semifinal games, when they were on a sensible day like New Year's or something. I have little interest in the new format, and I'll find a 12-team playoff to be even less compelling.
Obviously I'd watch if Texas were ever in it, but that doesn't seem to be a likely scenario anytime soon.