That is an interesting idea. I'd probably leave it up to the G5 to see if they wanted to do that. Because I don't think it's necessary to prove that the G-5 rep belongs.
No, I am complaining about making it more difficult than it needs to be. And you keep saying "prove it on the field" but my system does that better because it isn't giving an unnecessary advantage to one team. Plus, as Madguy pointed out, there's differences between the NFL and college football so the fact that they use a bye-system doesn't mean as much.
I think the committee is probably here to stay. They aren't giving their power up. But even if they did. The system is still going to be biased. Even if you use computers it's going to biased. Computers will just perfectly use the biased system that you told them to use. It could also lead to absurd results depending on how you were having it determine who should get in.
Sure, that could happen. Or where Wisconsin won the Big 10 at 8-5 because Ohio State and Penn State were ineligible. But in that case they would just be the 8 seed and get demolished. Also, the only people who would really be upset in either of those cases are other Pac-12 teams or Big 10 teams.
My concern with just having the computer choose the top 8 is that computers aren't perfect. They just do what you tell them to do and value what you tell them is important. So if you don't have autobids, the computer may say that the best 8 teams are 4 sec teams, 2 Big 10 teams, Notre Dame, and Clemson. Plus, if you do an autobid system, then everyone has a path to the championship.