The Unbalanced heros of LOL

I mean I can't be the only one to have been chocked to be dps by a nocturne lvl 5 non feed like he was lvl 18 with 2.10 stack speed, or roll on by the majority of the op champs like shit juste because they are unbalanced, It is too much, there aint a single game where one of the heroes is gonna roll on anybody at some point without having been necessarily fed before. and everybody has to shut it, hope, and get killed !??! where is the fun in the GAME, when you know, and you just know it ! that this is gonna be 15 min to struggle and being annoyed without any hope because one in the team doesn't surrend. I know I am not any particularly good player, but I played long enough to see how the game changed, in good but now ... it is getting bad. I don't know if riot want to pray on the few that are gonna kill everyone and be unkillable, like that the rush on the fun is high, but for the others ... it aint the same .. it is realyyyy low.