Turret's Damage.

Hello Guys, Most of you might have noticed how in starting midgame, the tower gets useless. Ofcourse I don't want the near tower area to be "Almighty Save your ass zone", but it's damage is useless from mid-late game; thanks to the high HP the items gives to players.

How about turret's damage is made in such a way that the turret deals "XYZ % of max HP + ABC Damage" as damage instead of it's regular damage? Then regardless. The "XYZ" amount can be small, and "ABC" damage about same (but bit lower) tower damage as it already is such that in early game the change would be negligible.

Please comment on what you think about the idea.