If you notice, RIOT is busy working on aesthetics/"cute"/"kawaii" things and draining the cash cow before its milk goes rotten.
There's so much wrong here. I don't know how many times it has to be said that different teams assume different responsibilities. You cannot say "RIOT is busy working on aesthetics" when the thing you want fixed CANNOT be fixed by the manpower going into the ART department.
Also, "draining the cash cow" in this case makes zero sense. League of Legends is an esport on top of everything else, meaning that just trying to suck all the money out of it IMMEDIATELY is a HORRIBLE business decision. Publishers can do that with shit like CoD or Battlefield because those games come out every year or two, but league is a consistent things with no sequels. The "draining the cash cow" philosophy would be a horrible decision.
Furthermore, some skins are banned not because "they are too noisy," though I can imagine this being a reason for some. Skins are banned from competitive when they too heavily alter a champion's silhouette. Something like Pulsefire Ezreal is not immediately recognizable by the uninitiated to be Ezreal because their silhouettes are so different, while something like DJ Sona can be allowed (I presume) because that sillhouette is still distinctly recognizable as Sona regardless of your familiarity to the game. There will always be a touch of subjectivity to this, so its hard to say what exactly should or shouldnt be allowed, but in the end this is Riot's decision to make pro play look more exciting to people who aren't necessarily league players.
**TL;DR - Skins team can't solve client issues. Draining the cash cow is a horrible business move for a league of legends style game. Banned skins from pro play are done so primarily because of readability issues for people who are not accustomed to the game environment.
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If you haven't noticed, about 90% of the time, the latest champion will always be the most powerful, or have the best kit for the current meta.
I'm sorry what? Are you implying champions are released specifically when they can do well? Champions take MONTHS to make. They can't predict the future. Are you saying these champions are always popular and therefore "meta?" Because thats not how it works. THey are almost always somewhat popular because they are new, not because they are perfect for the meta. Everyone wants to play with the new thing.
Now, if you are saying Riot deliberately releases champions when they are overtuned? I'd agree with this somewhat, but it also makes sense. It is MUCH easier to tune a champion down, than up, to start with. If they are too strong, you can simply take down what makes them strong, or take down everything but their unique strength to make them better off. You wanna talk underpowered releases? Gragas. Old gragas was released in a buggy underpowered state. So everyone avoided him. So they buffed him. But everyone STILL avoided him because of the stigma attached to him. What happened? He ended up being the strongest mage in the game without any hint of it showing until he exploded into every queue across the world as the most dominant mage in the game. I'd rather something obviously strong tuned down over time than have a sleeper timebomb ready to destroy everyone because no one knows about him.
TL;DR - Riot can't see the future. Champions being released too strong and then being tuned down is much more reliable than other methods of tuning new units.
Don't get me wrong, I hate plenty of shit Riot does, and I think they can do better. But your criticisms lack substance.