In the movie promo we saw Sarada gearing up as well so I don't think she'll be getting placed as a side character. She'll most likely be the 2nd lead.It'll be some real BS if Sarada and Sasuke don't get at least half the development Boruto and Sasuke receive. I'd really like to trust Kishimoto and believe he'll somehow combine the two things so that there would hardly be room for complaint.