Well her tradional attire is her trademark so if they want from people to recognise her they must put her in her tradional attire but still if there is a photo of all the princesses together with their huge big puffy gowns she would look like an outcast

This one.

If they can switch it up with Ariel being a mermaid and in her pink dress, I think they could do Pocahontas in both her regular outfit and in that ballgown she wears with her hair down.

tha ball dress was in Pocahontas II and Pocahontas II doesn't exist in my mind.Also in official disney club,parks,disneyland and so on Pocahontas is an official couple with John Smith and not with John Rolfe.So it would be contradiction Pocahontas to be with the ball dress in disney princess line or on DP merchandise. I don't think she'd look like an outcast.Pocahontas is a free spirited woman she can't be trapped in a ball dress. Remember: Ariel wanted to be human but Pocahontas didn't feel well.She wanted to go as soon as possible to her home.

even if she seems out of place in the group, i prefer this dress to the fancy one.
and she really has a cool outfit in the sequel when she's singing "where do i go from here"

I think she looks great in both but more people know her in her traditional attire so I would switch it up between the 2 :)

I know it's nothing like her, but OMG, that dress is gorgeous!