The question will be if it really does improve safety. If there's no change in injuries on KOs, then no benefit. Of course, with more touchbacks there will be fewer injuries because there's fewer plays. But I personally don't see any difference between starting at the 35 as opposed to the 30 on collisions - players will still be at top speed on impact. Only difference is collision will happen 5 yards further downfield.
The only "safety improvement" will be fewer KO returns.
Personally, the change doesn't really bother me. Probably because I'm kinda tired of seeing Pittsburgh's special teams get lit up at least 2 or 3 times a year. In fact, I kinda like seeing return guys having to make a tough decision when receiving the kick 6 yards deep in the EZ. Take a knee?...Take a risk? Make those squads earn their paycheck.
Getting the ball at the 20 for a touchback is too much of an advantage from the kicking team's perspective, tho. Move touchbacks out to the 25. And, if you really want to tinker, when the kicking team kicks it through the EZ, let the return team get it at the 30.