Teemo shrooms should last longer per rank

"Teemo should be buffed"

no.

Teemo does need some love to be honest. After the tank meta in s5 teams have stuck with the whole death ball strategy where they don't separate at all mid-late game. So Teemo as a champion who can't team fight relies on map coverage and utility. His shrooms can be used to secure different objectives and provide vision, but I think that a five minute duration from ten hit him pretty hard.