A few things I noticed after playing him/with him a bid.
Monster Benion … That thing can be a hit or miss. You can get an early monster and its fine. Or you get a late monster and its pretty irrelevant. Or you get no monster at all and without doing anything wrong half/third of your passive is wasted.
Ult Effect … The bright light when he ults is extremely annoying when you are playing as sth else and he is inside/close to you. Basically takes all your vision.