This is what I have in mind. Simply just make tower hit two guaranteed shots no matter how far the enemy is, so long as they went in tower range to begin with.
Now before you downvote just think of it this way. Mobility champs have so much advantage over normal champs like 
etc that I only see this as the actual solution.
if played right 
can tower dive you and not even take a shot.
Youre actually, mechanically wrong though. If zed aggros tower, he's going to take the tower shot even if he flashes flashes away. The tower shots auto track no matter what and the only way to dodge them is by becoming untargetable. Also, mobility champs are better than immobile ones.
edit: the only way zed can tower dive someone and not get hit by a single shot would be if he used all his cooldowns, ulted to become untargetable before the first shot him him, and then warping away with a shadow without damaging the champ anymore. In which case his ult is doing less than an auto attack.
OK so now any champions that have CC that displaces the enemy character model are gonna be OPOP cause they can push you into turret range to feast on a minimum of 2 turret shots even if you flash out of range. OK OK GOOD SUGGESTION!
no must be one of the worst things i've ever come across on this board...and there's some real stiff competition there.
Well, turret shots cant miss unless one of two things happen: 1)the champion becomes untargetable(stopwatch, GA, very few abilities) or dies before the turret can hit them. 2) the turret is destroyed. When a turret is destroyed, the shot does disappear.
A guaranteed double shot would just be clunky and weird. Having the first shot do extra damage or temporarily increasing the tower's attack speed for the first couple of shots would be a better way of punishing aggression.
I certainly wouldn't mind it if the towers were more threatening in the early game. Give them a buff that lasts for the first few minutes that amps their damage to champions so long as a friendly player is standing underneath it, like:
This would make towers scarier in the first part of the game so long as they are defending someone trying to hug it, discouraging tower dives and making towers a safer place while still allowing people to get that last hit in under tower if they really want to (killing the champion means there's nobody to proc the higher attack speed). Tower dives are exciting plays, so they shouldn't go away entirely, they should just be riskier.
Make them do mixed damage as well. I'm tired of champions like Akali being able to build just a Zhonya's and suddenly be able to go under towers for free. Make 55% of the damage physical and 45% magical so that towers hurt everybody.
i wish towers would just do a flat %hp true damage. so tired of a super tank running under the tower, taking like 10 shots and then running away because he was able to auto me to death and take like 20% damage lol. i also hate when you just happen to take a tower shot and it does way way more damage than you expect. like adc take 2 tower shots, then you take 1 and you die at 50% hp because the tower hated you lol
