I think straight up buffing turret health, especially to the degree that you're suggesting, would be overkill and result in a lot of turtle strats that lead to uninteresting or not very interactive gameplay. Turrets should be strong enough to play around without making it impossible for the offense to make meaningful advances. Whether that's the current state of turrets or not has been and is still frequently debated.
My understanding is that outer turrets are strongest to ensure that there is a laning phase (how long that should be is also up for debate) so that champions that are supposed to excel in that phase of the game do get a chance to shine. I do not, however, understand why Nexus and inhib turrets were nerfed so hard considering they protect important pieces of your base and are your last lines of defense. The explanation they gave was:
"We want to give defenders something to feel good about when they do hold off a push on their base, while also giving sieging teams meaningful milestones other than just "tower destroyed.""
Taking an inhib turret or nexus turret and thinking all you accomplished was "tower destroyed" is a very shortsighted way of looking at it, considering what you really accomplished was getting an open inhib or open nexus for the rest of the game and gold to boot, what players choose to do with those advantages is up to them. As for the turret regeneration changes that were supposed to be compensation of some sort, I almost never witness them since these turrets rarely ever survive one siege. So it really feels like all we got were straight turret nerfs which means games end faster.
Unfortunately I don't see Riot reverting the 8.11 turret changes because I think they're afraid it'll kill the bot lane diversity we've been seeing (and which they seem to want to preserve), since stronger turrets favor marksmen who can siege safely and efficiently with their range and attack speed.