What would probably work well would be a semi-open wiki, rather than totally open one (or a rather closed one as it is now). Each entry could have comments, the team of moderators would check comments for accuracy and update the entry itself when new facts come to light. People would not be able to edit the original entry itself without being volunteer staff.
Meanwhile, instead of waiting on the moderators, people browsing the collection would be able to evaluate the comments using their own judgement.
The "common people" could just send in a new song or version with a form, then moderators would check and click "approve", rather than waiting on hard-coding the data.
The difficulty in coding such a system would be the cross-referencing, the tunes, a really robust search, and setting up permissions on who can do what to the information.
I'd also add in a song rating system, so instead of 300 comments along the lines of "Ooh, I love this song!" people can vote that they love it, and keep the comments for facts about the song and it's background history.
I've been doing more programmatical (is that a word?) websites lately in php/mysql, and do have a lot of time on my hands. However to take a huge project like this on I'd definitely need some pay.
Perhaps the mudcat complainers would like to get a fund together for hiring someone to make a semi-open wiki version of the DT?