The future

Gimp 1.4 will be a cleanup-version.
objectifying lots of the Gimp internals
prepare stuff to be incorporated in a Gimp 2.0

Gimp 2.0 is completely vaporware yet. Of course lots of cool stuff is planned:
Colorspace-stuff (GEGL: 16 bit, CMYK)
Layer Effects, Layer hierarchy
Module Tools

Gimp 2.0 will need time. It is scheduled as a complete rewrite -
to get rid of the 0.54 mess.

Lots of fun ahead!