Sterling's a brilliant player. He's their top scorer. You don't stay in their team, in a key role, unless you are exceptional and you deserve it. Aguero struggles to get a run of starts for them. Criticising someone as good as Sterling is pure Kopite gobshite behaviour.
He's a good player who looks better due to his pace and the players he plays with. He'd get in any team in the league, but the chances he misses near enough every week shouldnt be being missed by a top top player.
He's very lucky to have been in 2 brilliant attacking teams that gives him more opportunities than you get in normal teams. Look how different he is for England.