I want to push back a little bit on this by framing it a little differently. I can't speak for the others who want to expand the roster and pick up the pace, but my reasons should not be viewed as some kind of a major rebuff on Geno's coaching.
His record speaks for itself, mostly using a more limited rotation, but occasionally expanding it a little more when he has the talent. Beyond the pros and cons of game strategies, which have been debated effectively on both sides, I also look at this very much from a recruiting and program strategy standpoint.
If your coaching strategy is to use the best 8 players only until mop up minutes, how does that coexist with recruiting a roster which next year could have top recruits on the third team, not just at number 9 and 10. Maybe the thought process is if you can't make the top 8, screw it, go ahead transfer, who cares. Could Geno win that way? Of course, but is that what's best for the program?
I don't think recruiting way beyond your intended use is good for the program. Do we want to be one of the programs that leads the nation is players leaving? If Geno sticks to 8 next year, that is probably what we will be.
Many coaches have a favored approach or strategy that they really would like to pursue, but have to mold their approach to the hand they were dealt, or the talent at hand. In this case Geno recruited these kids, and at least for these back to back classes got much of what he wanted.
Most of the people expressing their opinion here have strong feelings about whether the team would be better or worse expanding the rotation, I get that. What I am getting at, is it is not just an issue of which approach produces the largest margin of victory. If it was even close to a neutral, I would still be in favor of expanding the rotation, because if gives at least some meaningful minutes to more of the roster, and increases the chance we can retain more of them.
Geno could even expand the rotation for the vast majority of the games and stick with his comfort level in the handful of games that really matter. That might make the people on both sides of this issue happy. Play your favored 8 against say Baylor and South Carolina, and a rotation of 10 or 11 against everybody else.
Next year I don't think there is any lineup Geno could put on the floor that is likely to shrink the lead against most teams. This year it might somewhat, but against the teams where the outcome is not in doubt, does it matter if we win by 36 or 37 instead of 40 because we increased the minutes for players that don't get any prime time action?