While I agree with the premise of an 8 or 16 team playoff as that will definitely grab the best teams and is the most fair, as an independent, we could be left in a lurch trying to schedule games. The current champion will likely play 15 games (unless it was ND, we'd only play 14). That's a 12 game season, conference championship, and two game playoff. That's a lot of games at the college level.
I played at Grand Valley and was there during the transition from Coach Beck to Coach Kelly. Division II has a 16 game playoff, but the regular season only consists of 11 games with no byes. The season rolls straight into the playoffs with no break, so you end up with 15 games straight. Translating that to FBS, do the teams give up their regular season byes? Does everyone have a bye week before the playoffs? But the most important issues for ND are I don't think you can play a 12 game regular season with a 16 team playoff so where do we get our opponents?. Do you play 11 or as few as 10? As the number of regular season games shrink, do Power 5 mega conferences have any non-conference room? If they do, are they going to play ND or a "warm up" team? Another very important issue is the playoff would at least start if not be a couple games in during finals. For those schools who actually require their players to attend classes and take finals - like ND, that can be a real disadvantage.
Don't get me wrong, I do not like the current format, but there is an opportunity cost with an 8 and especially 16 game playoff and that may be ND's independence or at least the ability to schedule some interesting games. Just my 2 cents