I don't think it would be that high. Isn't there only like 5 yards between the kicking team and the receiving team? That's a small window to hit, and there would be risk involved. If the kicking team doesn't place the ball between the 40 and 35, then they would have missed the landing zone and the receiving team gets the ball at the 40 (like they do when teams miss the landing zone now). That would add a level of precision to the effort because NFL kickers would have to practice getting the ball over their teammates and not past the receiving team. Ideally, they would want it to hit between them and take a hop.
I think it would be kind of fun to watch as kickers hit their teammates in the back or kick it too far, and certainly if they landed it, there would be a mad scramble for the ball since there is just the 5 yards between the teams. Would change the dynamics of kickoffs if teams at least had that option. Does the blockers let the kick bounce past them and have the return man run up to fall on it or do they try to catch it?
I don't think teams would use it much because of that small kicking window, but having the option to use it changes strategies and brings back the element of surprise and gamesmanship.