So I created a smurf to see the "new player experience"
Now because I am not a total dick, I play like top tank jinx, or ad swain mid. Because frankly I would feel bad for absolutely destroying these new players. The thing is some people who are obvious smurfs just go an wreck these new players like go 20/0 in lane and tower dive these people who don't even know how to build a champion yet.
Another thing is you are constantly put against people who have keystones. My account is level 3 and I will go up against people who are level 23, 24 ETC and these people have massive advantages on me, they may have runes, and they have keystone masteries.
All in all if I was a new player, I would probably quit league because its not fun. My Girlfriend wanted to quit league because frankly she doesn't have any fun when shes not playing with me.
You need to do something about the new player expierence if you want to keep new players riot.