There's really no need to roll unless you want them. The upcoming Summer units range from great to decent. Notably, Archuria is the best ST Arts spammer who offers great survivability and back to back NP nuking. Tamamo is much more situational since her skills are gimicky (imo), but she serves a similar role as Bryn with a mix of self and a team buff. Martha is an offensive Ruler with a gorilla deck. The rest, I'm not too sure since I never had them in JP but I hear Caster Marie is the only black sheep in the group (take this with a grain of salt).
If you think you need any of these, then feel free to roll. Although a good sidenote would be that Chloe/Kuro (welfare for Prillya) functions as an SR Archuria, so that's something to consider before dumping all your sq on her banner. Chloe basically outdamages her in NP (coz NP5) but has lower back to back NP spam potential and replaces Archuria's heal with an evade.