If there surely was a handy and possible level-editor in JJ3, It would be easy for me to give my vote for it. But as now as neither of the projects are going ahead, and there's no knowledge what kind of features they would have, it's hard to cast a vote on anything. But I'm still giving my vote for jj3 for now, but of course I wouldn't mind if 1.25 was made. It would be sweet if it had exactly same features as the April Fool's hoax.