Agreed, virtually all of my PCBs’ sizes are limited by the convex hull of the front panel parts. On top of that, I’m pretty sure the area term in the PCB cost calculation is based on (max width) x (max height) , so there’s little point in going for any shape except rectangular.
Take the polymorph per example: Polymorph analog VCO . That’s a 250+ part project, yet there’s plenty of space for THT parts and routing.
The only upside of SMD I see is the possibility for automated fabrication. But then again, I don’t really mind the soldering. Is it really DIY if you’re not sniffing them vapours?