I think there is merit to having a "casual mode" in the designer, where say, instead of putting in and configuring each part one by one, you get subassemblies of entire rocket sections reminiscent of kerbal, that all fit together like a jigsaw puzzle to each other. Of course they can still be broken up and super-tweaked as per usual, but I think this could relieve some complaints of JNO being too complicated / too hard.