Long time fan of XMP for the reason you mention and for others (such as displaying the contents of a script tag for human consumption–read, “learning/teaching examples”…and then being able to use the same piece of code to run it as script–the ultimate DRY). I gave up long ago trying to convince folks to reconsider XMP–as long as browsers provide support, I’ll leave the politics to the politicians. But if you gain traction on your quest, you’ve got my support.