One of the biggest problems I've noticed in the QC verse is that happy couples tend to fade into the background, whether it be Dora and Tai, Pen-Pen and Wil, Steve and Cosette, or Claire and Marten. We also haven't seen Dale and Marigold in some time either.
Because of this, I imagine very soon Jeph will introduce a new conflict, whatever form that may take (not necessarily between some of the main characters, I can also imagine some kind of 'foe'). Likely something related to the feelings Bubbles and Faye have for one another that may go further in one of them then in the other.
For Marten, it would be interesting to see him make a serious switch to a different career, or maybe do a story line about his band performing and maybe having some success(?).
Don't expect much in the way of storylines for Will, Steve, Dora, Marigold, or even Veronica and their relationships. It's pretty much Faye/Bubbles central now for the most part.
The return of Angus would be interesting, especially bringing along tensions with Bubbles.