So, here's the thing - every champion in this game is easy to play. None of them require any real god-life mechanics to succeed with. What these players in Bronze and Silver do (myself included) is position poorly, go in when they shouldn't, retreat when they shouldn't, and focus wrong targets and objectives. I can play Shen about as good as anyone, but it's decisions like when I ult, when I engage, when I try to sneak in a dragon, what items I take, what jg path I take, when to counter jungle, when to gank, when to farm, where to ward, where to check for wards, etc. that kill me. This game is about strategy and tactics more than mechanics.
Most Bronze and Silver players also blame their teammates way to much instead of taking personal responsibility or just acknowledging when the enemy plays better in general.