Why do I have to accept the 16th team in the nation having a shot at the title? Oregon State (BCS 16) is a good team, but they're not anywhere in the conversation.
As far as conference champs go, the Big Boys schedule Sun Belt Champ Troy, for example, as a "gimme" win. Now you want to let them get a crack at the NC? No thanks.
Ohio State is supposed to play Penn State again? I thought that was already settled.
I don't mean to minimize home field advantage, but that hardly addresses the casual fan. What do they care who plays at home. Ohio State and Michigan fans will always care about the game, but when Ohio State is 10-1 and Michigan 3-8, no one is tuning in to see if the Buckeyes keep home field advantage. They have this sort of scenario in the NFL, and I can honestly say I have never once tuned in to a game for this reason.
You may have a point about motivation for the players, though I'm dubious how strong a draw home field advantage would be in terms of being "up" for a game. But, CFB is also business... The current system keeps people interested. Home field advantage doesn't put buts in seats or turn TV sets on.