In-form Nadal is much more consistent than Murray, it's a no-brainier. Of course, what kind of form Nadal is going to have next year is unknown.
more consistent ? well imo in last two years Murray's focus only was on one thing : winning a slam (and the Olympics), and he finally did it. He clearly showed that he didn't really care the rest, skipping at last minute, etc ...
Before that, Murray had great streaks in MS1000 tournaments (between mid-2008 and mid-2009 he won nearly all of the MS1000 tournaments on hardcourts).
I don't think it's so much about consistency, it's rather about being "better".
But Nadal's peak was reached in 2008 and he has physically declined since then, Murray's peak was reached last year and nothing says that he has reached his final peak yet imo as he rather improved in last years and has a lot of weapons in his arsenal and typically those players need time to find how to fully use them well in the end.
Anyway, I understand these arguments but I think Murray is very underrated in this forum, and Djokovic, who imo played his best tennis last year in the end (from Beijing) and the very-beginning of the year (in Australia), had incredibly tough matches against Murray in those "at his best" period last year.
I'm sure Djokovic himself doesn't underrate Murray as MTFers and especially Djokofans do.
The "wind" thing is bullshit : we're not talking here about a player who had one fluke run, we are talking of a multiple slam-finalist, multiple MS1000-winner and Olympics-winner.
Besides, of course I agree that the "defending" thing is irrelevant but it was brought by a Djoko-fan to minimize Murray. It seems to me that a lot of simili-arguments are made to minimize him here, the source of that is not reasonable imo, it's purely subjective : so many years laughing at Murray, and so many years being scared of Nadal left a deep subjective print