https://www.leagueoflegends.com/en-au/news/dev/quick-gameplay-thoughts-addressing-mythics/
Why we’re removing Mythics and the future of items.
It's a good move. The game could stand being a little more simple and back to its roots.
They should also remove the bottom turret being weaker than the others. It also adds unneeded complication to the game, and is an extra hurdle for new players.
Blast cones and honeyfruit can also go while we're at it. Maybe the vision and ward clearing ones can stay. At least those have a more interesting tradeoff. I'm not sure if they net positive or negative vision.
Plates were a great addition and should stay.
I love all the fruits, they add interesting plays and possibilities. But I agree that the bottom turret shouldn't be weaker. That's weird.
They did it because pros were opting into bad lane matchups and then just swapping their bot and top. And if the enemy matched, they'd switch back.
People didn't like the fight avoidance in pro games.
I kinda wish they would have given it more opportunity to work itself out.
I know it wasn't the most exciting game play, but there was a chess match-like mental mastery to the whole style that I really enjoyed when teams pulled it off well, like CLG did (I was a fan of them). But it's not as exciting to watch as the hyper aggressive style that China brought, so I get that, too, and it also invalidates a lot of champions when there's barely a lane phase.
But I think you're right that it would've been good to see how people adapt to it. I never followed it, but I've been told that Brood War (and Dota maybe?) had many meta updates just from people adapting to each other without any mechanical updates to the game.