Is Napier better than Mullen…?
Too soon to tell. Napier is unproven at this level.
In terms of building an infrastructure of a program, yes.
He puts effort into recruiting and seems to be putting effort into the job. Mullen never put effort into recruiting, and stopped putting effort into any aspect of the job in 2021.
Mullen is a better offensive mind, though his philosophy is out of date. Trask forced Mullen to adapt a different one, and to his credit, Mullen did pretty well with him (although Brian Johnson deserves a ton of credit for that as well too...look at Jalen Hurts on the Eagles, Brian Johnson is the real deal). I do believe if Franks never got hurt, Mullen would've been fired halfway in his 3rd season at Florida. That 2019 team was ASS, especially on offense, until Trask took over (despite Mullen doing everything he could to not play him while Franks struggled).
Mullen could not hire a DC worth a damn while at Florida. Will Napier? It's hard to say if last year's defense was so bad because Patrick Toney sucked or because the players were terrible after 4 years of shytty Mullen recruiting and shytty Todd Grantham coaching. Maybe it's a combo of both. But if Napier can hire a defensive staff that can improve the defense, I'll say he's better in that aspect too. He has yet to do that, but he has also yet to prove that he can't do it either. Again, too soon to tell.
All I know is Mullen's last season ended at 5-6, with Greg Knox beating FSU to get them bowl eligible. I truly believe if Mullen didn't get fired after the Mizzou game, that FSU would've beaten them.
Napier just finished 6-7. Pretty much the same as the year before with a harder schedule (Utah is tougher than FAU, FSU was much better in 2022...Mullen's game against Bama was tougher than @ Texas A&M, so that could cancel out one of those games).
We'll see if Napier takes a step forward this year. If he takes a step back, or does about the same, then questions could start being asked.
As of now, he inherited a program that was in terrible shape because the last coach was ass at developing and building a sustainable program and pretty much maintained the status quo on the field while attempting to tear down and rebuild it.