It would be simple to eliminate kickoffs and still get the same dynamics and strategy of the game.

Whenever a kickoff is called for, instead give the kicking team the ball at their own 35 at mark it as a 4th and 15 play.

That team could then (1) "go for it" making it like an onside kick situation, or they could (2) opt to place-kick it, which would likely land in the end zone resulting in a touch back, or (3) drop-kick it, which would probably land inside the 20 yard line as a fair catch. 

Options 2 and 3 both set up the possibility that the receiving team will be able to return the ball, but with fewer players colliding with each other at high speed, because in both cases any "gunners" the kicking team sends down can be pushed the whole way.

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