Major red flag for me was that he made it about himself. "I'm coming" was literally the message. I'm coming. Screw you. I'll get us winning. (ETA: That's incorrect. "I'll get *them* winning.")
I understand what he was trying to do. Establish a culture where he's probably been told one doesn't exist. But you have to be careful what culture you you replace the old one with.
I have a ton of respect for Heupel and the culture he's built at UT, and you can see the benefits. The whole is performing as greater than the sum of the parts. And he did it by establishing a selfless, team-centric, mutually beneficial culture.
It is the exact opposite of "it's all about me, what I will do, with or without you; I don't care which."
Heupel is all about, "Let's invest in you, to make an us. If you refuse that process, it's on you. But we're here to improve you, and as each of you grow, so does the team."
Much better than, "I have nothing for you if you can't benefit me. Be enough or be gone."