We're not pulling tower damage all the way back. If current is ~20% buffed, the target is ~5-10% buffed relative to previously. However, we think tower damage being too high has some undesirable outcomes.
- Dives being weaker than intended has some negative effects on punishability of champions and it removes a satisfying feedback loop when playing the lane well. We don't think you should always be able to convert a lane victory into a kill, but if previously, you could dive and escape ~40% of the time after putting the enemy in kill threat range, it's probably closer to ~15% of the time now. This makes the game have less rich decisions overall and less forward momentum (especially in high level play) because the optimal play more often than not is to let them recall, rather than take a calculated risk. This makes the game less fun in the long run.
- As a person on the receiving end of dives, I can see the perspective that it feels good to be more resilient to them, however the current damage amount is frequently shocking, expectation breaking and dissuades action.
The bolded part is the most important. The optimal version of League of Legends is not one where it is not possible to kill champions, even though it feels bad to die. On Patch 12.10, champions are significantly more difficult to kill in the early game, which is desirable and we plan to keep it that way. When coupled with the turret damage changes, I think it's gone too far. When the incentives to pursue aggressive action are too low, it makes the game too low interest and less fun, even though I agree that it isn't fun to die (eg. 0-0 kill meta).