Featires in dream maxgui designer?

I'm doing a gui designer for max gui, just wondering what your dream features for such a product would be.

One idea I'd like feedback on is using a dedicated custom formtat and providing a module that loads/save it rather than generting raw code, which I find a hassle to use. What do you think?

Generate raw code, and let the user type the variable name for each control.

Copy Delphi

Copy Visual Studio 2005!

The Properties dialog is the key from my point of view