I think this is the natural (over)reaction to the ESPN Highlight culture that swept college football the last decade or so. Everyone likes being on TV, so those big hits became more and more the rage. The NCAA is reacting to that by trying to ramp down on the massive hits, and in typical NCAA fashion they're going to overreact and mire the game in unclear rules.
Clowney's hit in the Michigan game would get him tossed, as would Kenny Bell's block against Wisconsin. Clowney because he led with his helmet and Bell because he "launched" himself.
Clowney could have turned his head aside, which is what the officials are saying they want you to do, and that would likely be safer for both him and the RB. But that play happened SO FAST that I can see why he hit the guy the way he did. The after-the-fact second-guessing of players' actions is what's going to suck about this rule. From snap to tackle that play took what? Three seconds? From the instant Clowney burst through the line until he hit the RB was less than a second. When you beat your guy and have a clear path to the ballcarrier, you don't have time to line up your hit in a textbook fashion. You just hit him.
Bell's block would get him tossed not only because the guy was "defenseless" in the officials' definition (which is stupid) but also because Bell gathered himself before the hit and launched himself into the other guy. He also hit the guy around the head/shoulders area, and they're really on about that kind of hit now. Only problem is, that block was a textbook form block, the kind of block that, in the absence of these new rules, Husker coaches would be using as teaching film for years to come. Bell had to "launch" himself because the guy weighed near or the same as Bell, and was running pell-mell down the field. Bell would have gotten blasted himself had he not delivered the blow.
These are major, fundamental changes to the game. The intent is noble - player protection - but the method is, as is usual for the NCAA, ham-handed.