phreak ran some numbers on it in his patch overview. i think it was, if the damage split is 50/50 champs/minions it's a net 0 change, If damage is more champs then it's a buff to towers, if it's more minions then it's a nerf.
Basically, dedicated pushes should be a bit slower (not really by much tbh), minions passively crashing into the towers should do more.
It's a lot more complicated and situational than it looks, but it really doesn't seem to have changed much in the grand scheme of things. Dedicated pushes will still work like they always have, so the tower takes an extra auto, big deal. Rift herald is still stupid, and now if the enemy pushes a wave and recalls, or is a tank/wave clear champion that doesn't do much damage to towers by itself, then the tower will die faster.