matchmaking

i understand that matchmaking will try to put me against good player to improve myself but it's really necessary to put me against platinum and diamond players? i'm a bad player, i can't last hit properly, i will often press flash by mistake or try to catch that one enemy with 10 hp because i believe i can kill him while i often get killed because of the useless chase under the turret and it's ok if i play against someone of my same skill level or a bit higher but against a diamond? well it's lost in the first 5 minutes if they go in my same lane... i understand that ranked and normal are 2 separate queue but i think it will solve alot of problem to new players if ranked 5v5 matchmaking formula could work with normals too, so a diamond that never play normals doesn't go against a level 10 that can't play properly please riot think about it, it's frustrating for a new and mediocre players to play against platinum and diamond