I quite liked Legacy (Tron Legacy is a better The Last Jedi then The Last Jedi) so I'm a bit disappointment that this doesn't seem like it follows up on anything from that movie.
Yeah, unfortunately the Tron 3 that was an actual sequel to Legacy was torpedoed after
Tomorrowland flopped. Disney took that as "audiences don't like non-Star Wars science fiction" and scuttled it.
I am a Tron fan, and I'm still not sure how I feel about Ares. I have reservations based on what I've read, and I don't like Jared Leto as an actor, but I'm willing to give it one chance. I mean, it might be great! But I'm going in very cautiously.
Man, Disney still doesn't know what to do with Tron, do they. There's the Legacy-based rollercoaster down in World, they're finally kicking Ares out the door, there's a trickle of collectible merch thanks to the parks, but...I dunno. Ares is something like the third attempt at a third movie, they did Uprising so very dirty with scheduling and lack of advertising (and then never releasing it physically either), and other than that there's just nothing.
Friend and I were talking about the very subject, and he floated that if Uprising hadn't gotten cut off at the knees - if they had gotten just 2-3 more episodes to wrap things up, they could have pivoted, made the story flow into Legacy and make the show's case of prequel-itis actually mean something narratively. Like, let the show end with Tron turning into Rinzler, Beck taking the Tron name as a codename (which then uncouples Boxleitner from the role), and Kevin & Quorra disappering into the outlands. Would it have been clunky and kinda depressing? Yeah, probably. But it would have had some flow and some story meaning going into the next (timeline) movie.