I wouldn't say James deserves more credit but he definitely deserves less blame.
The guy hits one wrong note and gets jumped on for it. People who slag him for mistakes seem to forget that the human voice is affected by pretty much everything... age, cankers, temperature, humidity, smoke, altitude, health, etc whereas physical instruments will sound the same no matter what and it takes an actual injury to the player to mess that up. Look at Petrucci: he had a cold during SCORE and I've read other times when he's been too sick to do much other than go right to bed after a show to rest but during the show you'd never even notice.
I think it's cuz everyone has a voice but not everyone plays an instrument. What I mean is that, as a guitar player, I can hear when Petrucci or Satch or Blahblah mess up, but a non-guitar player (certainly a non-musician) might not be able to unless it's huge flub. People can relate to vocals and therefore can more easily pick out any mistakes. It's also why I think shows like The Voice are so popular, cuz everyone can relate to them, but similarly-based instrumental shows would fail except for people who can. I'm not a drummer but I always read about the drummers here pointing out little flubs MP and MM do, things I could never pick out unless someone told me.
So, yeah, not more credit, but way less bashing.