Midwest will always be at a disadvantage when so many Bowl games are played in the southern teams back yard.
That's pretty obvious, and is one reason you can't compare the conferences solely based on bowl games. For example, at the recent Dollar General Bowl, Troy fans outnumbered Ohio fans by what, 20:1? It's not quite a home game for Troy, but close. It's not a deciding factor, just a small advantage for southern teams.
I'd be careful reading too much into a single year's bowl record. Sometimes there is the luck of the draw, and you get mostly unfavorable matchups, and sometimes you get favorable ones. This year the matchups weren't favorable. I think Toledo was a pick-em, and everyone else was an underdog. As a contrast, back in 2011 the MAC was 4-1 in bowls, which, as I recall, was the best of any conference. Does that mean that in 2011 the MAC was the best Conference in America? Hardly. It just means that in that particular year the MAC got uniquely favorable matchups.
So, how would I rank the G5 conferences? For 2016, I personally would rank it this way:
1. AAC
2. MWC
3. Sunbelt, MAC (tie)
5. CUSA
For 2015 I think the MAC was ahead of the Sunbelt. How will the two compare in 2017? I have no idea.
Why do I put CUSA behind the MAC? To me the difference is at the bottom. This year Buffalo was pretty awful, I'll grant you, the worst single team in either conference. Other than that, though, the MAC didn't have any really horrible teams. The next worst, as a group were Ball State, Kent, BG, and Akron, which in my mind were all pretty close. I think that all four of those teams would be favored in a game against any of the six worst teams in CUSA, Charlotte, Marshall, FAU, FIU, UTEP, or Rice. [Yes, I just said that probably the only MAC team that Marshall could have defeated this year was Buffalo.] In fact, there were two matchups from these two groups this year, with Akron beating Marshall, and Ball State defeating FAU, so there is empirical evidence to support my opinion.