Hah! The "I'm going to pretend to be a drill sergeant!" mentality. Surely if you act tough and behave like a jerk, people will respect you, right?
The truth is, you just can't fake that kind of thing if that's not who you are. Urban may have gotten away with it, but that's likely who he really is. Players understood that from him because it was real. Herman sounds like he was trying to play the tough guy. Texas players have seen tough guys in their lives, and Herman wasn't it. Instead of motivating out of fear, it just fell flat.
Sark seems like the enthusiastic sales guy. He's glad you're on the team! He'll smile and shake your hand. He'll show you the plan, give you everything you need to succeed, encourage you, give you tips when you're flagging, and still be smiling when he cuts you loose for not making your numbers 2 quarters in a row! If you're not getting it, there's three guys waiting for your job.
He emphasizes trust = time + consistency. I believe he's consistent because he's being his true self. Playing for Texas can be fun and enjoyable. You can build camaraderie with your teammates and position coaches. Ultimately, though, it's a privilege. If you don't do the hard work and produce at a championship level, you'll be "future endeavor"ed.