I'm considering participating in Google's Summer of Code - I think this will be a good push to get me into more open source development, especially with MusicBrainz. I'm also perfectly eligable, and often bored in the summer... so why not! I'm trying to think of some ideas, so I'm sketching them below. Note, this is a scrap page for my self, so many of the ideas may not be thought through - but if you do have some constructive feedback (even if it's, "This won't work because of X") do feel free to add it :)
OR... redesign? MusicBrainz has kept the same design for a long time, and while it does work - maybe it's beginning to get cluttered. Change is not always a bad thing either. This project would consist of working closely with those responsible for MusicBrainz reputation/image firstly and getting a design, then implementing this design and finally integrating it with the new Python-MusicBrainz server.
Adaptive Search Results
A lot of editors here work on specific sets of music (I myself, work with drum & bass) and often for editors we have to move through extra "noise" in the system to find data that is useful to us. Adaptive search results would attempt to filter, or prioritize search results in some way to make them more useful to specific groups of people. One way to make this work, for example, would be to move any results in an editors subscribed artist list to the top, or emphasis the results. Other changes might be to prioritize artists the editor often works with, or has "visited" more of.
The edit page currently requires a lot of clicking and waiting. This can be improved a lot by having one edit page that changes as data is entered. This is not only faster for editors, but is more user friendly, and may help get even more edits in quicker. For examples, check out the submission forms for discogs.com and rateyourmusic.com
Extend XML webservice (submission/edits)
The current XML webservice provides a robust way to retrieve data, but no way to push new data. Some people have requested this support, this project would implement it.
More web service bindings
I've a bit of experience with the web service, so I could write bindings for another language to the web service.