I don't that the DOJ can demand more minority-majority districts that are erose, and not dictated by adjacent communities of interest. So I don't see a lot more being demanded myself. But the law in this area is tough to get a handle on. Muon2 keeps reminding me of that, the bastard - he knows just too damn much!
I don't think that they can force additional seats under preclearance under Section 5, which is to ensure that there is not retrogression of voting rights. Perhaps they can require maintenance of proportionality when a state is gaining seats.
What the Supreme Court ruled was that the Austin-McAllen district didn't count as a VRA district, since it was just an attempt to categorize persons by race. If that district had counted, then it didn't matter what had been done in TX-23. It appears that the district court extended that and avoided drawing districts linking the border to San Antonio, and this could be considered a precedent in other places.