I would like to see prestige become more elastic. Here is what I mean.
Right now, if you coach a low or mid major D1 school, your prestige is essentially capped. It is mighty hard to get it above a B. Meanwhile, at a B10/ACC/SEC/B12/P10 school, your prestige has a hard floor. You will never see a D+ Wisconsin team, no matter how bad the coach is.
What should happen is that both of the ceiling (on low and mid majors) and the floor (on high majors) should soften. If a low major coach goes on a 5-6 year streak of 20+ wins, conference titles and 2nd round NCAA appearances, their prestige should be able to reach B+/A-. In other words, a highly successful mid-major coach should be able to create the next Gonzaga and have a high enough prestige to win recruiting wars.
And a bad P5 team should be able to have a low prestige. If the team is bad enough, it will lose sway with recruits. Right now, do you think most top HS players would rather play for Gonzaga or Minnesota? Butler or Boston College?
But those teams should quickly revert back to the mean under "average" conditions. If that high-flying midmajor coach leaves for a P5 job and a SIM takes it over, the team will quickly revert to a "normal" C-/D+ prestige within a year or two. And if that same midmajor coach goes to a downtrodden C- P5 team and has some early success (like a winning record), that team will quickly revert back to a B- prestige team.
Under this system, prestige would work less like a ceiling/floor and more like a gravitational force. A midmajor has a strong gravitation field to pull its prestige down, but a really good midmajor can build up enough success to overcome gravity. And a P5 school has a weak gravitation field that will allow it to quickly take flight again.