I agree.

The forum default doesn't render properly width wise on the device, which I find really puzzling, as it is otherwise pretty polished (and I think a paid for custom theme). You have to change to classic to eliminate the horizontal scroll bar.

Text fonts could be a tick bigger to read more comfortably.

Page navigation requires pin point precision to hit that tiny little page # and I personally would prefer that all pages are listed (so not 1 2 3 ... 25). I've set my forum preference to 40 (the allowed maximum) post per page to remedy this somewhat. Still, on the desktop I'd probably prefer to get all posts at once.