It isn't a surprise at all. Reports of him wanting to move out have been doing the rounds for ever. That was the whole point they roped in Fahmaan and introduced Aryan. Fahmaan and Aryan both became a resounding success and the risk of the PH losing the show with GM's exit is now negligible.
Sadly, fans made the reverse of it and assumed that GM is being ignored because the PH wants to push Fahmaan as the ML. Even for a temp period, a show can't do without an ML and the show won't shut shop because the ML wants to leave. GM has the right to make his choice and so does the PH. This way, it just works out for everyone involved.