It's been decades since the adult Titans did anything worthwhile though. I can't even remember the last time there was just a good Dick Grayson focused Titans story. So it isn't like the Titans brand is doing the adult Titans any favors in the comics.
The Titans as a brand will never be able to move on from youth being a core part of their identity. I can't see it ever happening. That is the identity of the Titans as a franchise. Some people want to say "family" is, but it isn't. It is about young heroes. That is the most consistent theme of the teams since its creation. It is about young heroes growing up, and as long as the adult Titans are on a Titans team they will never break away from being "young heroes". Which will always put them in an awkward position of being too old to really be considered "young heroes" anymore, but too young to be on the level of the JL generation. So they end up being stuck in this awkward position of being neither and no one knows what to do with them. They have grown out of the core Titans theme, but they keep getting shoved back into it because that is what the Titans franchise is about.
The X-Men team's core identity was about mutants and mutant survival. So even if they also had young teen characters that grew up right along side the Titans characters the core identity of the franchise, mutant issues and survival, remained the same even when they moved far away from it being about young heroes. The Titans don't really have any theme like that to lean on now that the original Titans are all adult and don't fit with the core theme of the franchise. They end up just being another hero team that feels like a JL knockoff with no real direction.
I mean Wally and Roy have both been part of the main JL team. It is about having a creator want to use them in the title mainly. I mean Snyder's JL run has had a ton of focus on Hawkgirl, who isn't really an established JL fixture run after run.
I don't except any of the fab five to replace the main JL characters, but you are kind of stuck with two choices in the end. Continue with what the Titans have been for decades, constantly trying to reclaim their peak from 30+ years ago without being able to shake the identity of being "young heroes", or move on and try to join different adult hero teams. Sure, most of the adult teams, like the JL or JLA books and their spin offs or anything else, will not last long like most team books now, but I'd rather see them try to integrate into those books than to continue to be stuck where they are. Give me more things like Cyborg and Starfire on a cosmic JL team, Dick leading some JL or DCU spy team, Raven in JLD, Wally teaming up with the JSA for a while, Beast Boy back with the Doom Patrol, and so on to see how that works out over another uninspired Titans revival series.