Skillshots are boring, overdone and they are a direct contributor of power creep

First: skillshots are boring. They are a very safe and plain way to design a champion but they have had the effect of making most matchups incredibly reductive to how well your champ can avoid or negate the other's skill shots. "Move to the left or right" being the main way to outplay most of the roster isn't interesting. To add, most skillshots have a strong anti-melee effect because they travel directly outwards from the caster; this means that someone in close proximity or who is trying to close the gap will have a much harder time avoiding it than someone who is staying at range. I'll add to this in the power creep section.

In addition to that, because skillshots are already variant by nature of being missable, the opportunity to create real strategic value in them is heavily limited; you cannot add 'niche' things like very specific debuffs and empowerments because they are skillshots and lack deliberate targeting. Instead, any tack-ons to a skillshot will always be very general so as to not feel 'bad' about hitting someone you didn't want to. Examples include armor/MR shred (universally useful), soft or hard CC (universally useful), vision revealing (universally useful). We are denied a huge portion of potential gameplay because Riot's philosophy (and player ideals) have shifted to every champion always being useful in most/all situations rather than champions being specialized for specific goals.

Second: they're overdone. Not everyone champion should be designed to have a skillshot. They're not terribly offensive but the overuse of them leads me to feel like the roster is becoming more homogenous. (Semi-related, I feel the same way about fighters and attack resets; I really fucking want it to stop). There's nothing inherently wrong with all-melee champions or targeted damage. It's entirely in the way that Riot has implemented them. There's plenty of ways to lever-tune targeted effects.

Third: power creep. There's a sense of deliberation with targeted spells that simply don't exist with a lot of skillshots in LoL. Choosing who you want to hit vs just throwing your rotation out where it's most likely to hit someone or where it'll hit the most people. Because Riot wants skillshots to be more rewarding than targeted spells usually, most skillshots come with multiple effects, as listed before. They'll be AOE, they'll be more spammable, and/or come with CC attached, and you can see this trend in a lot of recent designs.. Because of this, and the aforementioned anti-melee bias that comes with straight-line projectiles and the general mayhem of teamfights nowadays, melee champions simply cannot afford to wade through a fight anymore. Thus, they become more mobile to dodge the slew of skillshots, or get packed with more tank spells so that if they DO caught they don't immediately die to the handful of massive AOEs that weren't even directed at them, or they themselves get more skillshots - and thus, more range to hit YOU from a distance before they have to put themselves at any meaningful risk. Champions who are mostly melee-focused or short ranged who have to commit to going in and have difficulty getting out have been struggling for years now because of this. This is also why Vi has such a difficult time measuring up to Camille despite being at a respectable power level; Camille can poke before she goes in, she can dodge incoming damage better, and she can easily escape if she needs to.

I know that most of you have a bizarre hatred for all things targeted and anything that is obviously biased towards stats and numbers more than your "epic outplays," but I've been mulling this over for a while. Skillshots are not innately bad, but they're certainly too common and I would say their frequency and their sheer power has been a net negative to the game's integrity.