First of all, while it is true that we don't know how much time they have been working on the new models, there hasn't been any real confirmation about the topic until a year ago or so.
I've seen Vaanel models (the best player-made ones I've seen so far), they look good and I'm sure he has put a lot of effort into them. But none of them have new animations. In fact, he shows very few animations in his videos because he has edited the model around a certain pose. As soon as those things begin moving, they'll clip badly.
So no, making 16/20 new, customizable, fully animated models that still feel like the old ones, takes much more than 'a few months'. Unless, of course, things like the female worgen and, to a lesser extent, female pandaren happen. Those are perfect examples of rushing models to make them in time. And I don't want my character to become a much more polygoned, better textured piece of crap. I want them to do it RIGHT and deliver the quality they promise.
I'm personally inclined towards the "next expansion, as a selling point" view - I'd say given that only the Dwarves have been mentioned as being finished (or at least, in a near finished state) so far, that it's extremely unlikely we'll see them during MoP. I'd probably say given this that it's actually more likely to not even make the launch of the next expansion, and instead be part of mid-expansion patch - 6.2 perhaps.
All of this of course is speculation, with a little sprinkling of common sense. But only that is enough to tell you that they almost certainly won't appear during MoP, nothing more.
The closer we get to Blizzcon the higher the chance is that the new models will be announced during it and released next expansion.
If they're released at any point, it's 5.4 at the earliest. BlizzCon announcement+reveal is more likely.
I'm hoping that the new model roll-out (whenever it hits) will maybe include a backdoor fix of worgen females, and maybe a couple more faces for fempandas.
"Stop being a giant trolling asshole." - Boubouille
"The Internet is built on complaints about asinine things" - prefect
"Facts became discussable when critical thinking stopped being the focus of education."- Chonogo
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Would like to prefer that Warriors/Death knights be more wider broader, melee DPS orc like Rogues be more slimmer but more cunning looking, and casters slim too. Like these 3.
Warrior/Death knight:
Rogue, Monk orcs:
Casters:
War is deception, a game played best from the shadows!