Turrets are bad for all the wrong reasons, imo. They feel really weak really quickly, and even when a team pushes a single lane heavily the inhibitor turrets don't feel spectacular. At the same time, just buffing them numerically would likely just stretch out games, which would be far worse overall. The bonus effects added during the Summoner's Rift overhaul also mostly either shrunk to really weak levels (e.g. tier 2 turrets and their personal shield) or just disappeared completely (e.g. beam turrets having a slow and damage reduction effect). Beyond that, I think there's also a serious issue with turrets discouraging melee champions from pushing as part of a team, due to how they end up being exposed, which just encourages top laners to splitpush even more when the rest of the team is grouping, and is likely one of the reasons why marksmen are such a fixture in every game (nobody else can push turrets with the same level of speed and consistency). On top of this, turrets don't feel particularly valuable, again because they quickly lose their threat, which is why items specifically designed to interact with them in some way (e.g.
,
,
) aren't nearly as popular as they deserve to be.
Farther down, I think Riot should attempt to do a few crazier experiments with turrets, minions and lanes in general. Black Market Brawlers was a great experiment in making minions more interesting, and while brawlers might be a bit too complicated in the long run, I think there's a lot of stuff that could be put in place via both minions and turrets to make lanes and their structures feel more powerful and interesting without jeopardizing the game's pace or clarity. One thing worth trying, for example, would be to have turrets spawn minions at their feet, rather than the nexus, which would eliminate proxy farming, and another potential experiment could be to give one type of turret an additional shot per enemy champion in range, which would discourage ganging up on lone champions under their tower. Perhaps some turrets could just not fire any shots at all, and instead have other effects that would influence laning and champion interaction.