There needs to be two types of helmet-to-helmet fouls: One called targeting, one called helmet-to-helmet tackle.
The helmet-to-helmet tackle is the one where the tackler is trying to go low and make a proper tackle, but the player with the ball is in the process of falling or sliding or lowering his own head which puts his helmet at the level of the player making the tackle. That should be a 10-yard penalty and an automatic first down.
The targeting call is when the tackler lines up and crown pops the receiver making the catch across the middle, or the QB who has just released the ball. 15 yards, automatic first down, automatic ejection.