This. I only even learned about the 17" dolls with the release of the last set of Anna/Elsa and had no chance to get the first four. The last Anna with her end-of-movie outfit I actually prefer to snow gear Anna, but the purple dress Elsa isn't my favorite outfit or hairstyle, so the FF one I'm dying for since I'll never have 2000 bucks for the Snow Queen one, and I loved FF.
I mean they should absolutely get to characters they haven't done! I'd love a Mulan doll, for example. (Although I just know they'd put her in the matchmaker scene dress, which I hate so very much, and not her dress from the end of the movie when she's busy actually being *her* instead of some fake nonsense society is forcing her into, which makes me sad.) But I'm happy if they do new versions of ones they already did that I never had a chance at. (A less ugly Ariel I can afford? I'd be all over that, you could do some gorgeous things with the purple dress Triton makes for her at the end when he turns her human again! Or her blue peasant dress she wears for most of her time with Eric!)
Oh, we all forgot the mourning outfits from Frozen.