I'm still RL fishing as far as WoW's concerned, but thought I'd put out this guide for tanking as a Moonkin. I don't think it's nearly as controversial to consider the moonkin as a tank for relatively major encounters as it used to be even a few months ago, as this WoW Insider post helps confirm. For fun, here's the movie.
The guide linked to, above, still doesn't give us the proverbial mathes for bear vs. panzerkin threat, which I still need to get around to doing, but let's just say that unscientifically, moonkin can step in there and keep the squishies from going dry. Of course, as all of us PUG junkies know, it's just as much knowing how to tank as having the gear, talent, etc. Man, how a good tank makes PUGging more fun -- though admittedly it's not as important as lucking into a good Priest. I'm going to pause for some silent reflection. Phew, good Priests are nice.
I'll put a hard-copy of the moonkin tank guide here just because the Blizzard forum posts, even some sticky ones, disappear every so often.
Totally randomly, I'll append that the Death Knight seemed to make a lot of sense until I figured out that it could be either Horde or Alliance. I'm not totally on top of the late breaking info on the next expansion, but initially I thought having a flood of new high level Horde characters on Proudmoore would help balance out the numbers in the battlegrounds a bit and shorten waits. I will say that I'm much more likely to put some serious time into a higher level alt than a brand-spanking new Blood Elf. They're fun, and I've leveled a draenei hunter a bit, but I still don't have anyone over 10 but my main. I'm more confident now that's all the Death Knight is: An attempt to get those of us who don't want more lowbie alts but would pour in a few more months' of gameplay if the alt was as interesting as our main.
Now even after saying that a high-level alt would be attractive, note that the Death Knight seems to be a hybrid that's a lot like the Panzerkin. This is a magic using class that can tank. The difference? Well, instead of inserting an extremely round peg (those moonkin are pretty healthy, ain't they?) into a very square hole, these guys get to toss mana and rage entirely for that rune jive. Probably a smart move. Maybe something similar can happen with 'kin down the road?