I've never played the games but I enjoyed season 2 and season 3 looked to have a clear direction. We know where it starts and we know roughly where it ends and I'm guessing the finale will match wherever the game's story ends.
The only controversy I could see is what direction the show is going to take after the third season. AFAIK there is no more material to pull from so we either have to end it or write something completely new.
Going in a new direction without the original writing team can be tricky, but also it sounds like he's leaving on good terms so he could always come back.