What's wrong with the design? It's nice, clear, and doesn't waste resources - i.e. loads quickly. It's dumb to demand a new design just to follow questionable aesthetic trends that change every few months. What's the problem with keeping a system that works? After all this forum should mainly provide useful content and information and not be a catwalk for hipsters.
A very important advantage of this forum is that it works without JavaScript. Out of security reasons, JavaScript is disabled in my browser per default. I can't even load the new beta forum without deactivating various security settings.

That is idiotic - a forum primarily displays simple text. That should be possible without scripting!
ya.ya.yo!