Marsch is an interesting study. Accomplished enough that he was offered a job in the Premier League to salvage Leeds season. He did it, just barely.
He's recruited fairly well, his players seem to be willing to die for him, they've actually played ok, but results haven't gone their way.
I think he deserves more time. There are far worse teams besides Leeds, so I'd be surprised if they keep dropping points. That said, they should have a few managers on speed dial just in case.
As for the personality stuff, ultimately it's all white noise. I think people enjoy making fun of the Americanisms and have been waiting for him to fail so they can feel smug. For this reason, I want him to succeed.
I'm from the East coast, so his earnestness and Boy Scout type bearing seems weird and foreign to me too in a way. But his players love him, so his personality seems to work. I find his sideline demeanor really off-putting, but he's less annoying in interviews.
Not my cup of tea personally, but looking at the other Prem managers, few of them are either!