The sunbelt is still much weaker than cusa was at any time we were in it for basketball.
The hypothesis that the Sun Belt is "much weaker" than CUSA, either now or in the recent past, is not supported by data. Yes, CUSA is ranked above the Sun Belt, but the gap is comparatively small. Last season, out of 32 total conferences with auto bids to the NCAA Tournament, Sagarin ranked CUSA as the 12th best and the Sun Belt as the 15th best conference. Ken Pomeroy had CUSA ranked as the 13th best and the Sun Belt as the 17th best last year.
You might be surprised to learn that this season, both CUSA and the Sun Belt have improved their conference rankings. In a composite conference ranking considering over 40 different rating systems, CUSA this year comes in as the 10th best conference, and the Sun Belt as the 13th best conference, out of 32. Interestingly, the MAC has dropped to 18th in these composite rankings.
Those same composite rankings have the Herd currently at #69 (about 30 spots better than the 2018 Elmore squad that beat Wichita St. and higher than any other Sun Belt team so far this year). CUSA's highest rated team is UAB at #55; the MAC's Kent comes in at #56.
https://masseyratings.com/cb/compare.htm