It looks like his rip/rake uptime is quickly diminished on bosses where he has to move or do something other than just stand there and dps.
Possible solutions are having him to get a dot timer to make tracking the dot durations easier and setting up a power aura to yell at him when either dot is down or having him stack haste or crit instead of mastery. The differences between the various secondary stats for a kitty are quite small. The fact that he's stacking mastery causes his sub-par uptime on rip/rake to be emphasized.
cut him off of catnip, and only give him some after he performs well, soon enough pavlov classical conditioning will kick in and he'll top charts everytime ;>
As someone mentioned, uptime on rake and rip are terrible. I suggest Need to Know as an easily configured and visible buff/debuff tracker. It takes all the thinking out of what button to press. All he has to do is track Savage Roar, Rip, and Rake and his dps will improve a lot.
Other than that, someone correct me if I'm wrong, but I see fights where they could be using shred that they didn't at all? Cats get screwed on a lot of bosses with positioning, but this seems a little subpar. Additionally, I don't think ferocious bite is being used properly when the boss is at low health to refresh rip. I see this mistake a lot. It effectively just adds the damage of 5pt FBs on top of your already sustained dps.
With their gear, they should be doing WAY more dps.
He reforges for mastery, yet his uptime on bleeds is pretty bad. Looking at Morchok (H), Rip and Rake are both up around 50% of the time. Black Blood phase doesn't last long enough for it to kill uptime that much. As others have suggested, he should be doing much more dps.
Tigers Fury only last like 8 secs but if a rip or rake is aplied in those 8 seconds it will keep the buff for its full duration.
black blood phase of murchok is an awsome time to put up an TF boosted rake & rip before you move out of the blood and then heal yourself up whit your own mana and you dps will go up and healers should not QQ