I've pretty much watched all of the Derrick Henry Vs. (insert school here) videos on YouTube that I came across.
Henry just seems to be considered a power back cause of his size. Calling him a power back is kind of the same as the people who call every white receiver a slot guy or compares them to Wes Welker.
I don't really see a power back style when he runs. When you do watch other "power backs", he doesn't run nearly as violent as they do. Because of how big he is, getting his pad level as low as them seems to be a problem, and he has very sub par balance. Marshawn Lynch had very good balance, which is why he was able to stay on his feet when he would head on truck people, bounce of tackles, and when he would get hit in his legs.
Yes, I saw a few plays where Henry stiff armed a player. But when I think of a power back style, I personally think Lynch, Bettis, Ivory, Campbell, Marion Barber, Alstott, and players like that.
Also, I'm not calling him a bust, I'm not writing the guy off. I am actually looking forward to seeing what Henry can do and hope he kills it.