well there's different ways of looking at his results in 2016 under his calling. one is: his calling was exceptional but limited by his team or limited by his team. when G2 was at their peak in EPL/ECS, it coincided with the revitalisation of ScreaM and RpK's careers which led to them over-performing because of their newfound confidence. when that died off, they went into slump mode for the rest of the year, going out in groups and finishing in the 8th or 10th place. from that period onwards we can see his medicore, flustered and depressed IGL'ing.
basically, cuz he had some success somewhere in 2016 compared to his other buddies when they were playing like trash, doesn't mean hes a good IGL.