I think a Sinnoh remake is coming next, since we've recently had Gen 3 remade, but like ORAS I wouldn't be surprised if it works as a kind-of-sequel.
As much as DPPt are my least favourite generation (mostly because of the story and loose ends. Cyrus basically just vanishes and then Galactic disband? It just seems rather unrealistic and a bit weak plot-wise...) I really feel with the premise of Ultra Beasts and Wormholes they could really make the Sinnoh story into something amazing like they did with ORAS. The set up is already there for them. Dialga and Palkia are pokemon of time and space, and Giratina lives in another world. I wouldn't be surprised if the Distortion World ends up being a form of Ultra Space and Giratina turns out to be an Ultra Beast. Its Origin Forme does look rather strange compared to other pokemon. Maybe Cyrus has no idea and ends up accidentally unleashing Ultra Beasts into Sinnoh, or the story could pick up where the first DPPt ended and have him make his way back out of the Distortion World only to be followed by the Ultra Beasts? There is so much they could do with this, and I would love to see something a little different to the first DPPt games (and not just have Cyrus and Galactic vanish!)
I would also love a sequel to Sun and Moon, but after X and Y didn't get one I'm not holding out too much hope.