I think kickoff you will see moved to maybe a punt to start the game that way you won't total upset people who want a kickoff in some way to start the game. If you want a onside kick then I could see that being like a 4th and 10 or 4th and 15 play with offense on the field at your own 35.
I think what you will see is a lot more kickers kicking short forcing returns meaning you will have increased chance for injury. The NFL claims they worked with ST coaches for these rules. IMO these rules will not do anything to improve player safety.