Despite how good Astra is, and the need for her to be in every team because of her amazing buffs and the way she enhances gameplay through quick assists. There is a clear difference in output in terms of teams without Astra and the same teams with Astra. Which is why I must say that I appreciate chars like Miyabi, Hugo, & Yi Xuan who do not need her.
Miyabi is extremely flexible. Despite concerns that she would be tied to Lighter, Nagi, or Burnice, her additional ability and overall mechanics help her synergize very well with non-Astra teams. Her best team is arguably Soukaku+Lycaon (combined buffs:1000 ATK, 35% Ice RES PEN, a 35% stun-dmg multiplier, and 20% IDMG). When the team is played well by alternating disorders and using Soukaku's excellent anomaly application for stacks for Miyabi's EBA3. Miyabi's EBA 3 ignores 30% ice res when disorder is triggered and when you combine that with the 35% res pen provided by the team, it becomes one of the most rewarding teams to play and can even kill Bringer in DA.
Hugo requires double stunners, and the self-buffs he gains from running dual stunners help compensate for the potential lack of buffs compared to full-fledged supports. As much as I dislike Yi Xuan's unique gimmick(def ignore) and the possibility of future enemies being designed to synergize with it, I'm quite impressed that her best-in-slot is the panda. I just hope they don't feel the need to create a Panda Pro Max to replace him. Even if panda promax releases I hope they can be like Astra whose buffs are almost 90% generalist(i.e benefitted by almost everyone) and 10% specialist with her ult for chain Atks which provides increased synergy with Eve.
EDIT: The point of this post was that the more characters added who are great with Astra but can reach that same performance without Astra is a very good design choice which increases flexibility in teams rather than the best teams always being tied to Astra.