Personally, I've thought about making a gaming channel myself. I mean, I like playing them anyway and I just talk to my television. Might as well talk to an audience right? That's kind of how I see it.
"Call of Duty" and "Minecraft" do seem overrun. I see videos for them all the time, and never search for them. (Of course, I do watch other gaming videos.) There does seem to be a lot of people thinking "I'm going to make tons of money playing Call of Duty." That's just not realistic with the HUGE amount of people playing. If you are truly ENJOYING it though well go ahead, because it's fun for you.