As a fan of a school in the Big 12, I'm don't know that I even care all that much about which method (between these two) ends up getting selected. I know that my school (and the other schools in this league) isn't going to win a natty. I don't see a massive difference in outcome from one method to the other. I just want to know that my school is allowed to objectively play it's way in, and the game stops getting farther away from the sport I fell in love with. I'm fine with the allocation of the 4-4-2-2 model (I think it's fair), I just don't like the idea of an invitational (the codifying different strata doesn't bother me as much as it does the decision makers).
I think 5/11 because I think it makes for a better product (I enjoy conference championship games) and I think a pure invitational kinda sucks as a sports fan. I'll watch regardless as long as my school is allowed to participate.
This just doesn't seem like a situation with an obvious best choice from my perspective. There are existential risks in either path. We don't have much control anyhow, and what's going to happen in this support for good or bad will happen regardless of the Big 12 or ACC.