Didn't they move the kickoffs from the 35 to the 30 a few years ago, because there were too many touchbacks and the league wanted more offense?
Anyway, if the league wants to cut down on devastating hits, there's one solution: implement a PFD policy with real teeth, including blood tests for HGH. It's pretty clear that the vast majority of the league is on illegal substances, which leads to bigger and faster players, and thus, bigger hits.