Pretty much everything we've heard from the players confirms what people on this board have been saying for a while now. Ollie didn't connect with his players in a way that a college coach needs to be able to. I don't want to overstate that dynamic because I imagine even the softest college coaches are fairly ruthless, but comparatively it does seem like he was averse to holding guys accountable.
In his defense, that doesn't matter as much when your players are self-motivated, natural leaders. Jalen is not completely innocent here. The fact that Ollie inherited a team in mid-stride (and that's much different from saying he didn't coach them) may have briefly mitigated some of his weaknesses. Additionally, it's important to recognize that his demise cannot be simplified to a single personality trait. There was poor luck, there was (maybe?) laziness, and there was an unreadiness to run a major program. While there is plenty of reason to critique Ollie, don't expose yourself by picking a bad one. He can coach and I have no doubt that, assuming he's in the right frame of mind, he could take over a team tomorrow and win.
But this change is good, not only because it comes in time to resurrect the career of someone like Jalen, but also because Hurley brings a temperament that seems to work in the college game - especially in an era where most guys don't stay four years - much better than it does in the pros. You won't have time to burn out and assuming they're winning you won't have time to question his methods. If Hurley has demonstrated anything over his first few months - from re-recruiting players that were half-way out the door to exciting the fan base to getting the team to buy in - it's that he has his finger squarely on the pulse of player psychology and how to communicate accordingly. That's the single most important trait a college coach can have.