I'm not sure why I get this feeling that most people would underrate Joshs submission game. I'm not saying that he's a grappling phenom like Werdum, Roger Gracie or something like that, but he's every bit capable of submitting even the most "respected" grapplers in MMA.
I bolded the important parts there. Josh is a good grappler. He might not win ADCC or anything like that, but in MMA he's good.