edit: was typing this out while darnoc replied. I agree with him. leaving now would be a mistake if your goal is to get a big 6 job, just as people advised you after last season.
looking at the histories of my MWC teams: with C baseline, you'd probably get to C+ with back to back NTs. but maybe not given everything that factors in there. you also have to figure you had a losing season just 2 seasons back. plus, despite the gaudy win totals, your RPI (thanks to very low SOS) is pretty mediocre. not trying to say anything bad about your team, just further explanation for the slower prestige climb.
the upshot is that i don't think there's much of a discernible difference recruiting with C+ or C, it's pretty insubstantial.
In DI, prestige updates work a little differently. We look at the past 4 seasons and put a different weighting on each season. Basically, the further back the season is, the less weight it gets, and the less impact it has on the current prestige. Each season's success is based on the following items:
- RPI Rank
- WIS rank (the system used for the Top 25 rankings)
- Whether the team was conference champion
- Whether the team made the PIT
- PIT wins
- Whether the team made the National Tournament
- National Tournament wins
- Whether the team won the National Championship