I'm not sure about a rival, exactly, but the next party-group desperately needs way more contrasting characters. A major issue with Endwalker was that the Scions were effectively all on the same page about everything - Much of the time you could have easily swapped dialog between characters as they're reacting to events without anything changing. And not to go there, but a few conflicting opinions on certain characters from the Scions would have gone a long way towards a lot of people's enjoyment of both Shadowbringers and Endwalker.

More than anything, I hope we don't carry the Scions forward. I like them, but I've had quite enough at this point. There are many more existing characters that I'd like to adventure with, to say nothing of whatever new faces might come along. Instead of a group of sterling goodguy PHDs and genius savants, I'd rather have a more FF6-onwards type party of misfits who fill a variety of technical and narrative roles, and bring more to the table in terms of ideals and perspectives.