Is it not the case that last season teams couldn't really afford to double up on McFadden as if they did that Ojamaa, Humphrey or Law could hurt them? This season teams figure if they shut him down, they've got us beaten. Even first time around, he had guys like Elliott and Pearson to share the burden. But it was noticeable at the start of the second half against Kuban that they committed two or three heavy fouls on him, almost saying "right, target him, he's the threat".
As for the fitness issue, he missed the first week of preseason before we went to Spain. Perhaps the time when the most intensive fitness work was done? He should have caught up by now though.
For me, the fitness issue is secondary. The issue is less to do with that and the fact he's playing on the wing and more to do with the fact he's shouldering all of our attacking responsibility. He needs others to take the heat off him a bit...