I think that's a bit unfair. He's done a decent job for us, considering the managers he played for. Nothing spectacular, but not "poor".
In the CL games it looked like the players didn't give a damn about Moyes' plan. It looked more like a SAF team. There was actually some intensity and attacking play, whereas in the PL there was absolutely no joy or passion.
I don't think it's quite fair to put it like that. We won that title because of SAF, not because of our brilliant squad. If you compare our squad that season to those of our rivals that year, we didn't have much of an edge on them, even though we won the league convincingly. If SAF had stayed he likely would have made some serious changes the coming summer.
Likewise with LvG. The squad wasn't really a 7th place squad, so it's not like he performed some miraculous rescue operation by getting us into fourth.
But yeah, still not very debatable.