Better tools for graphic design. Maybe a port of the Affinity suite or a big push towards GIMP, Inkscape, and Scribus development. GIMP... I feel like people dreamed for more than a decade for essential photo editor functionalities like CMYK support and non-destructive editing. At least the first one is coming in the next version(partially).
I switched my design workflow to FLOSS tools exclusively. Krita is a perfectly competent photoshop replacement, Inkscape has been developed at a breakneck pace in the past year, the workflow is different, but it's every bit as good as illustrator, and Scribus is great once you get used to the workflow. If anything, Scribus' workflow helps you plan and structure your projects better. IMHO FLOSS tools are absolutely ready for professional work, but you cannot expect the workflow to match existing proprietary tools.
Would absolutely love for Serif Labs to create a port for Affinity Photo and Designer. Of the programs I've tried, those two have the closest UX to Photoshop and Illustrator without the software-as-a-service model.
Hell, I'd even take it if all they did was support it working under WINE. While I would prefer a seamless UI that fits in with both GTK and Qt, it's understandable that they might not consider it worth the effort.