So the Twin Suns expansion is listed under board games. but the hero and villian packs are under minis?

Descent second edition has all there products, expansions and mini packs listed under board games. Its the same type of game.

How about a little consitency FFG?

Legal reasons I would bet.

I read somewhere that FFG has the rights to Star Wars miniatures games (as well as some others), but not the right to board games. Hasbro still retains the ability to sell Star Wars "Board Games", whatever that means. And it really doesn't fit the mold of the question being asked, but it's all the info I have.