If the show lasted longer and been given a real conclusion, Throktar and Glimia would've eventually returned and either stayed in Udrogoth permanently or at least make arrangements to visit Oswidge and the kids on a regular basis.
Had the show lasted longer, there would have been an episode involving The Plague.
Since it's a pretty common theme brought up in works whenever the medieval era is portrayed. Oswidge dated Zonthara
When Dave mentioned to Oswidge on how breaking up with Irmaplotz went, Oswidge told Dave that he was lucky, as he mentioned that the last “evil princess” that he broke up with, has sent a group of filthy pixies invading the kingdom, which means that it happened once he broke up with Zonthara.- I can go one further. Not only could he have dated Zonthara,but their date (possibly a one night stand) may have resulted in Irmaplotz's conception. This might also explain why Oswidge and Irmaplotz both have purple eyes. In addition,Irmaplotz mentions she's "half good on her father's side". This goes a bit into Squick territory when you realize Dave may have fallen in love with his own cousin.
This series will come back in the form of a special on Disney+
If Louder and Prouder does well, Disney may try to bring back more of their older shows. With its Cult Classic status and a few loose ends, Dave's return could make for a big and welcome surprise.