First off, my preference is Zoog's fun option. 16, all conference champs and 6 wild cards. Allow for the Cinderella story.
Barring that, 12 with 5 Power 5 conference champs and 1 or 2 guaranteed slots to the other 5 conferences and the rest wild cards or 8 with 5 Power 5 conference champs, one guaranteed spot for the best of the other conferences, and 2 wild cards. Either of those would be a good alternative.
And regardless of number, like it or not, the weekly rankings/show is here to stay. Viewership is too high and creates too much good drama to not do it.