How many teams should be in the USA college football playoff?

The USA college football playoff currently picks the top four teams to determine the national champion. There were talks to expand the playoff to eight, twelve or sixteen teams. I think four teams works well but I think eight might also be fun. It's a physical sport with injuries so I don't think it's good to subject the athletes to another game against top-tier competition. I also think it's unusual to have more than two or three teams that are actual contenders in a typical year. There have already been a lot of blowouts with four teams and I think there would be many more lopsided games with eight or more teams.