Preseason rankings should just be for fun and rankings after that should fluctuate significantly based on results. Ultimately preseason rankings should be meaningless, in my opinion (I realize that's not the world we live in).
It seems to me where you and I differ is you want to find the best teams and I want to reward overall best performances on the field to this point. How about we do a hypothetical scenario for a second. Let's say you have two teams with comparably difficult schedules who are both vying for the last playoff spot. Team 1 has a record of 9-3 and team 2 has a record of 10-2. Let's say team 1 is favored over team 2 by a touchdown on a neutral field, has a huge talent advantage, and most people believe they are the better team. Which team should get in? In my opinion, the team with the better on the field record should get in, even though they may not be the best team by any other metric. I feel the same way about rankings. In my opinion, ND shouldn't be rewarded with a ranking until they have had positive on the field results. (Again, I realize this isn't how rankings work, this is how I think they should work).
I'll also point out that there's not enough data on any team at this point to make a final say on them. We think Miami and Texas A&M are good, but the data we have is limited.