As I write this I think the concept of a highly visual postscript editor is a dead end. There are multiple reasons for this. Because Postscript is so powerfull it is to slow to work with. You have to redraw the whole picture if you change one character in your picture because this one character might influence the whole. I think this will change in the future, but today a redraw tooks one to 20 seconds, which is to much for a continuous workflow.
Postscript is to difficult for a normal user.
Because of this reasons the old java GILT is dead. Gilt was a text oriented picture editor. Now, this is easy. You can describe every picture with commands like 20 mm 20 mm 40 mm 40 mm rect . This is done by every picture editor, sometimes scrambled in a special file format, sometimes in a open format like postscript or tex-commands.