how about to play the game in a competitive manner separate from ranked? Every toxic behavior in the game is amplified in ranked because the players feel like they are betting on a losing hand.
As per one of my other posts (I will fetch it if you wish but I found their discussion to be increasingly pointless), there were multiple detriments to making ranked entirely separate from normals and treating normals "as though it does not matter" even though a large percentage of players play normals competitively simply because there are fewer problems in normals
what you are describing is simply rational behavior. Everyone is going to practice against real opponents, people prefer normals over ranked because ranked players play as though they are the only member of the team that matters and that everyone else is a gamble.
as per your point about "you don't need to know all the unusual or off-meta strategies" , that is exactly what you need to know to create your own custom item sets, deviation strategies for your champion to react to the opponent, MOST IMPORTANTLY: strategies that you tried previously and would prefer to avoid because it was unsuccessful or did not interact well with a real team
the point of all of this: What "benefits" are there to riot's proposed change? it changes nothing and only causes more problems