Before someone comments on this being the wrong forum, I'm simply not high enough level to post in other forums, so here I remain for the time being :P
Now.... On to Moogle GLORY!!!
1. Why Moogles?
Frankly, Moogles are adorable, and every bit as iconic to the franchise as Chocobos. Not that there's any shortage of Moogles in the game, mind you, merely that being able to play one is something I think some fans have been hoping for in a game since FF6.
2. How would they even "work", wearing armor and using abilities?
I would have them display only your helmet, and your weapons would levitate by your side -- not completely unlike Sora's "Final Form" in KH2 (for anyone who played that game). Even with the most physical classes and jobs, Moogles would use their magic to wield their weapons for their various abilities.
3. Don't Lalafell already kind of cover the "cutesy" angel?
Well, sort of, but I think they're also very different. Humans and Miqo'te, for example, are quite similar, physically, save for a few minor distinctions, and I think Moogles and Lalafell are even more different. Plus, there's no way a Moogle would ever fit in a robe or suit of armor, so the distinctions would be even further evident.
4. What kind of customizations would they even have?
Honestly, their options wouldn't be nearly as robust as other races, but I think there's still room for variety. For one, they could easily incorporate tons of face-types, based on various incarnations (ie. the big-nose variant, seen in Kingdom Hearts), various fur types (smooth, rough, super-fluffy, or even "rubbery" fur), fur and pom-pom colors. I would even take it a step further, and have different types of pom-poms; Star and Moon shapes, maybe spikey-ball variations, just go crazy with it! (if you've ever played the Chao mini-game in Sonic Adventure 2, Chao are quite similar to Moogles but had a TON of Variety).
Biggest thing; more expressive faces.
If that weren't enough, another idea could be having a "Tribe" of Avarice-style Moogles. They're a little more humanoid, but still pretty awesome, and probably a little more traditional in how they could be implemented. I never played FF12, but when I saw their design, I knew that I liked it and wanted to see it again.
5. Do you really think Moogles are the best choice for a new race?
No. Surprise! I really don't think Moogles should be the immediate new race, because right now, more than anything, the game needs a more "serious-looking" race. I know people are clamoring for Viera, but I honestly think that would be a huge, huge mistake, as there isn't nearly enough visual-variety in the game. I'll probably post my own suggestion on that before too long, actually.
However, I *do* think Moogles should be added -- merely at *some* point in the future. They're crazy adorable, could have some pretty hilarious animations, and are iconic enough that I couldn't imagine a character I would want to play more -- especially seeing one riding atop a Fat Chocobo!!!