I also applaud nailman for taking the initiative to move the wiki to a more sophisticated site. But unless you remove the info from the old wiki pages and replace it with links to the new wiki pages, people will just keep updating the old one - not necessarily because they like it better, but because they have no way of knowing of the new one's existence. And those of us who want to read those updates will have to keep going back to the old wiki, whether or not we think the new site is a better option.
As the poster later wrote, it's a wiki, for goodness sakes. Edit it however you see fit. All I'm saying in terms of "people's choice" is that I don't care what people do. In my discipline, for example, since someone kept deleting our discipline's page again and again, I finally started the new wiki, and now everyone is using the page there. If that isn't the case for you, well, use the old wiki.
The only other option I can think of is to join the ranks of saboteurs and go around vandalizing the old wiki to try and get the people to join the new one. But that would be silly.
Suggestion for YOU: Just add links to the new wiki to your discipline's page, if you're even interested in using it at all. And add links to the old wiki from the new wiki page for your discipline...