MyPaint popularity is continuing to grow, much thanks to publicity from the Durian Open Movie project. We're now working on the v0.8 release, which hopefully will be out this year. I wrote a small post on the official site about that here. I'm responsible for the translations, and so far we have 11 of them, with a couple more in the works that I know of. Packaging is also picking up, soon most of the major GNU/Linux distros will have MyPaint in the official repos! Even some talk about a Mac OSX version (using X11.app tho).
I also plan to do some OpenRaster / GIMP-integration improvements and perhaps a small statusbar. I'm even considering writing a C library (with Python wrappers ofc) for OpenRaster, mostly to sped up saving and loading. A reference implementation would of course be nice to have.
But that is somewhat unknown territory for me and I'm not sure if I'm able to set aside the time necessary for such a task... We'll see!