Whoa, my mind just got blown a little bit, not by the miniature, but about my likely far-fetched assumptions. I'm more thinking about what this means for the Hobbit films than the fact that it's a new miniature of Aragorn (that doesn't particularly look too great imo, though the mounted version is in an awesome pose).

Is filming for the Hobbit completely done? Viggo Mortensen got asked to play Aragorn but never got a follow-up. If filming isn't over, there's still plenty of space for him in the film.

GW could, of course, simply go back and produce a miniature for the Lord of the Rings in the midst of the Hobbit buzz. I think that's the more likely scenario. But this model also could be an indication that Aragorn appears in the Hobbit trilogy. The films have a condensed timeline, I believe, both between the time between Bilbo's quest and his 111th birthday and between the 111th birthday and Frodo's quest. I'm guessing Aragorn would be in his twenties, and would be off fighting in Rohan, like this model suggests, during the Hobbit trilogy.

I think they've decided that Aragorn was a popular LOTR Character so decided to make another model of him

I think so too, my mind just went full-on speculative.

Pretty sure GW has the rights, they cover ROTK, and the appendices are in that book. For example the Necromancer supplement, Fall of Arnor, that's all appendices content. Even the scenarios for the the battle of Erebor, and Lothlorien, Mirkwood, etc. The sons of Eorl, Eorl himself, the wainriders, all appendix.