Were I to compare the hours I've spent enjoying Gears 2 online in the past week with the hours of amusement Yahtzee's provided in the last year, I'm sad to say that testosterone, soul patches, and gratuitous violence would be in the winning camp.
Yahtzee hasn't gotten less funny it's just that your hours of GoW have made you callous and cold. You may have some form of PTSD that's affecting your sense of humor. Unfortunately videogame veterans get even worse care than real veterans so I think you may be fucked.