More seriously, the trick I think with Processing is that it has been a wonderfully successful "stone soup". The IDE and its graphics architecture are left over from a different era and I can't see why it's language modifications are worth maintaining, but the vibrant community and library maker ecosystem is unlike anything else that's happening. But these two things are largely separable. The aim is to be able to connect with the latter while leaving the former behind.
Quite a few people are realizing this — for example, lots of people are justifiably excited about a JRuby / Processing mix. But the issue then becomes the lack of genuinely interesting IDEs. Netbeans and Eclipse make excellent hosts for staid, corporate, "large" programming but they aren't a good fit for something exploratory, experimental, time-based and live.
The questions then that somebody embarking on a new digital-art-code-thing are: 1) why a new language? 2) why not integrate into something like Eclipse? 3) and what are you going to do about your libraries?
Processing answers: 1) because html color literals are super important; 2) Eclipse is too hard; 3) we built it and they came.
OpenFrameworks answers: 1) Let's just use the sane subset of C++ and hope it doesn't get too out of control; 2) Let's just use a real IDE; 3) All the powerful libraries are actually in C anyway.
Field answers: 1) Languages are interesting but hard to get right --- let's have Python and a bunch of others; 2) Because Eclipse is too big, too boring and doesn't understand the live coding story at all; 3) Let's hijack Processing libraries where they are useful, and supply our own where they aren't.
Field is now in public beta.