To add unsolicited commentary, it would be nice to have a very basic default theme. I mean... NO "fun" styling, no CSS tricks, no images used at all unless necessary. (IE: No background images, but icons for actions are okay.)
The main/only thing I hate about SMF is how much time you have to dedicate to template editing trial and error.
Like... "Oh, here's catbg, that must be what I have to edit. No, wait... that didn't change the category background. Okay, I quit."
It would be nice to use a forum system for once that actually lets the end user have a blank canvas to style, instead of only putting in what the Devs think looks good, as that sort of judgement is highly subjective.