Interesting stuff, but everybody knows that Downing is having a shambolic season and almost any attacking midfielder in the prem would compare favourably with him atm. I remember someone here posted the chalkboard analysis of Downing's passing one time and rather than crossing it looks like he passes backwards almost every time he gets in an advanced position. So either his confidence is shot or he's being poorly instructed, or both. Last season he was immense for us, putting a lot more effort in than Ash did for most of it.
As for N'Zog, I've seen enough glimpses of quality this season to be confident that he will eventually come good. I think he's already been better for us, in a bad team, than Downing was when he was first playing under MON, and he'll only improve as long as McLeish doesn't ruin him by freezing him out.