There are a lot of pickers out west here saying that Arizona might have the best chance at winning the Pac 12 South, with both Darnold and Rosen moving on and the talent Arizona has returning. It’ll be tight and will probably depend on who they take, but I believe they would have a better chance with Sumlin, given what he could do with Rich Rod players - similar to what he did with Manziel. He’d fizzle once his recruits came in, but I think he’d be set up for a division title in year one.
I think Niumatololo would have similar results to that of his mentor, Paul Johnson, at Georgia Tech – which is to say averaging a winning record, but never enough to really compete for the conference title. Arizona players can’t even play contact until high school, so a down-and-dirty offense would be a pretty steep transition. California kids are mostly passing offense types, like what USC and UCLA have run for the last couple of decades, and the other mountain states nearby are pretty sparsely populated and less football focused by comparison even with Arizona.