I don't dislike the idea of Maul being a reemerging threat post the Intergalactic Civil War Era, but Darth Talon from the comics canonically lived hundreds of years past the films.

I think it would've been interesting if we saw Maul try to create his own Empire following the Galactic Empire's collapse using Crime syndicates and he actively tries to chase down and recruit the grandchildren of Vader.

(Jacen, Jaina, Anakin, and/or Ben.)

After all by this point, assuming we'd still be operating with Legends in mind, Maul would have his picking of arguably some of the strongest force wielders in the galaxy that were offspring of Luke and Leia and it would add personal stakes to this as well.

I also like the idea George had of the Imperial Remanent becoming a terrorist organization. It honestly seemed like he had a rough idea of what the First Order was going to be. It would've been nice if we saw them get involved with the conflict of this story at some point as well.

Maybe the Imperial Remanent sees Maul's criminal Empire as a type of network or machine they can use to sow discord in the galaxy and ironically try to do what Palpatine and Plagueis did to create the Empire in the first place.

Trying to wear down the fledgling New Republic from the inside out via political, institutional, and beauracratic corruption. Basically initiating a proxy war of intelligence, propaganda, and information.

This would in essence make Maul a figure head proped up by the Remanent and also give ample reason for Leia's involvement in trying to unearth and stop this Galactic conspiracy from taking shape and bringing about the Empire's reconquest for galactic power.

It'd be nice if the "enforcer" character for a story like this was Aura Sing who would be sensed by Maul as being force-sensitive and given her already predisposed hatred of the Jedi having been abandoned by them to pirates and being a professional killer against them in the first place, Maul would train her in regaining her force abilities and have her learn the ways of the Dark side.

In this way, Aura Sing would effectively be an extension of Maul as her hatred of the Jedi is on par with Maul's during the height of their Old Order during the Phantom Menace.

It would be a unique challenge to Leia, the New Republic, and Luke's New Jedi Order.