I think that, if I can say, that some of the problems are the many words and "lingo" people use in the game.
Such as, "hey, Drag in 15". As a new player, I'm not going to notice off the bat that this is about the Dragon.
Positioning has become TOO much apart of the game. New player, starting out, more than likely don't care about the jungle, yet I'll see many new "smurfs" come in, call a said position, and mandate what everyone does. That person, though trying to help, will start to lose, and curse, belittle, and say rude things to the teammates.
In all honesty, I think majority of the people who made it to Diamond+ are tired of the constant plays that always feel the same. And I wouldn't blame them. If I had a good duo top, like a Udyr with a Sona or Tryndamere with a Poppy. I've had games where, if my mid kept the lane even, we would push top very far. Especially if we worked together to kill the enemy. Then, one of us would go and push mid. Bot might be having a hard time by now, so mid guy can go bot and help with my duo partner. But, these don't always happen.
Or, we can have duo mid. We have the crucial position pushed first. We may see the person from top and bot go and try to help, which leaves a wide opening for bot and top to be pushed.
Solo bot, with duo's for mid and top. I'll solo bot and hold it until someone from top or mid can come and help for a while with nothing to hurt them.
But wait, what happened to the jungle? It's still there, but in my opinion, it was only made for quick buffs and quick CS.
Even when I jungle, I barely ever just run around killing things in the jungle. It's pointless. I gain way more levels just going in and scaring the enemy away from his farm. If I'm there, and there is no top guy, I'll push that lane. If I can destroy it, the enemy has nothing to hide behind.