That would be awesome. It could certainly use some improvements. Feel free to dive in and make the changes you can, though you should probably try to run any major changes past the broader community first. If you'd like to make changes that require more access, email team at arduino dot cc and b at progetto25zero1 dot com to discuss it. What did you have in mind?
I'd like to add a little CSS to the wiki, improve navigation to make it more intuitive, synchronize wiki registration with the forum registration, and make the wiki, forum, and homepage look a little more alike.
Would it be possible to duplicate the wiki so that I can make changes to it without disturbing the main site?
I've got a few extra servers here at the house. If it's too much trouble to clone the wiki, I could install PmWiki on one of my own servers and point a domain name at it.
Which would be best?
I use the same name, j0hn7r0n, for AIM, Yahoo, and Gmail. Feel free to contact me.
I used the homepage for the mockup just to see what it would look like. We can make the playground, forums, or anything look like this if we want to.
You'll notice the menu is stripped down. Humans (engineers included) like just enough choices to do what they want. We could leave the menu on the homepage the way it is, but I feel that fewer links would make navigation easier, particularly for new visitors. I figured the hardware, software, and hacking links could all be moved to a "reference" section of the wiki. The playground link would be kind of unnecessary if they're already viewing the wiki. Of course, we'd need to make sure all of the existing wiki links work and are not orphaned. Guide could be moved to either tutorials or reference.
Do we have a logo? If not, we should find someone to design one. We need a banner logo, a small logo, and an icon logo. Here's some banners I made with a few free fonts I found on the internet: