I think my answer to the top-level poll was the 1980s. That's convenient, because I was watching some college football then (although I feel in love with college football in the 90s), but to be honest, the main reason I think that is that it's old enough that it's the traditional conferences, it had a little more variety than the 1970s, which was a decade of traditional powers, and I can't stomach choosing an era before integration.
But my feeling about the current landscape is encapsulated by the Game of Thrones-style intro to the B1G games. Everytime I watch it, I see the schools in the midwest rising and I think: wow, that would make a good conference. Nebraska fits into it, but I wouldn't mind a world in which the traditional Big 8, or something close to it, were rejuvinated. And while I've always like Penn State in the B1G, it too, could easily belong to a Big East. College football was, for the longest time, quite regional. That's why it mattered how Wisconsin did against Iowa and Minnesota. That's why Cal/Stanford matters. And it's one of the things that made Notre Dame unique (thanks, Michigan).
For deciding the national championship, a 12-game playoff probably makes sense. You take the major conference champions, then you have to decide if minor conference champions deserve a shot, and if so, what about the major conference teams that had near misses, but have a good argument for being there. I think you could make it work with 8, but 12 isn't illogical. (The current seeding is.)
But the bowl games were special, and now they aren't. Now, that started happening when they started breeding like rabbits, I think in the early 90s. I liked 3-4 teams from a major conference playing other top teams from major conferences, but I never really cared about the Pinstripe Bowl, or the Music City Bowl, or etc., etc., etc. Sure, I would (sometimes) watch if the Badgers were in them, but they didn't really matter to me. The Citrus Bowl, the Hall of Fame (Outback) Bowl, they were still big games, even if the Badgers didn't make the Rose Bowl, because they involved top competition from other leagues, and it means something to make those games. The others? I remember when the Badgers played in the Copper Bowl after the 1994 season. Meh.
While it wasn't good for deciding a national champion, my grandparents (Cal, 1941) cared that the Bears last went to the Rose Bowl in 1959. My parents when to the 1972 Rose Bowl. It mattered to us in 1993 that Wisconsin hadn't been there in 31 years. The SEC loved the Sugar Bowl, I presume for similar reasons. The Orange and Cotton Bowls had great histories, and the Fiesta and Peach weren't far behind. That's all gone now. Yes, the names and locations are still there, but they aren't the same. And asking fans to travel to them is really just asking whether they want a trip for a playoff game. Nice, sure--NFL fans make those trips--but not the same thing.
And I'm not against the change--a real national champion is a cool thing. I just miss the charm of the old system.
Walking past Camp Randall it used to say (it probably still does) "the road to the Rose Bowl starts here." (Or at least something awfully close to that.) That meant something. Does it still?
If I were king for a day, I would instruct my minions to design 8 regional college football conferences that made sense, and try to adhere them to the conferences of the 1970s or 1980s (do I care whether Arizona and Arizona State are in the Pac-8/10? Not really), mostly because from a regional perspective, those conferences did make sense (travel was harder back then, so that's where the conferences came from). I think I would have an 8-team playoff that invited the conference champions. I guess I would force Notre Dame into one of those conferences, which is too bad because ND's independence is part of its story. But maybe undoing the anti-Catholicism of the 1920s Big Ten is appropriate in the modern age. Kind of feels like it. And ND could still keep its rivalry with USC, and its annual game with Navy. That would also probably bring back the Michigan-Notre Dame rivalry, probably with a little extra ire between those fan bases, which is a good thing for sports. For the teams that didn't make the national championship, I would restructure the bowls to reconstruct conference challenge games (bowls) for teams 2-4 in each conference (so 12 additional bowl games). Probably on a rotating basis, but maybe not. And all teams would get the same amount of practice time, regardless of whether they made the bowl games. Because conference championships and standings would be the thing that would determine entry into the playoff or the bowls, there would be more reason to schedule good OOC preseason games. They would generate more ticket sales and more TV revenue, and they wouldn't hurt the losing team. At least that's my theory.
That's how I would create the new golden age of college football (that and a collective bargaining agreement). Now all I need is a primary colored hat (red seems to be taken) that says Make College Football Great Again. (Irony intended)