I don't know how anyone can tolerate the sea of whitespace thing, I know I have sensitive eyes but it causes me physical discomfort to look at, it's like staring into a spotlight trying to read some text printed on the lens.
Same, so I like that backgrounds in this forum are not plain white.
From my experience, Discourse-based forums also show a lot fewer threads at once, it's annoying as hell when you're browsing topics.
Anyway, I don't see the point. Xenforo looks like a much better alternative, so if Dave decides to switch (and as he said, he'll need help anyway), I'm ok with this one.
Meanwhile, the current solution works. Software just doesn't rust. If it works properly, is stable and can run on any modern hosting service, why change it?