Here are couple more editor ideas:

Jazz Jackrabbit Sound Editor
Jazz Jackrabbit Language File Editor
-ablilty to make .j2s file in an easier way
-prevent JJ2 form detecting the file size of the .j2s file so it
dosen't end up telling you it is corrupted.
J2D Editor
-Behaviour Editor can be one editor within the J2D Editor
-anything that has to do with the behaviour of events (eg. enemy behaviour, weapon behaviour etc.)
-[any other editors within the J2D Editor goes here]
J2E Maker
-more formats than just .pcx (eg. jpg, gif, bmp etc.)
-graphical user interface for people who prefer a gui over a text interface

There probably would be no point in having a .j2h and a .j2i.