Wow, that does sound like a long job.
There is no single wizard to do something like this, and I think its a bit beyond the idea of wizards. I see them as a way to do a simple, quick job.
My first reaction is I would have done this job by using a CAD program to make the layout, then something like Sheetcam or Cut2d to make the gcode.
One way to do it with wizards would be to use the rectangular hole array wizard to create all the code for the array, then edit that code to drop in the code to make a slot instead of a simple hole. One problem might be that the hole routine uses canned drill cycles, you might have to hack that code a bit, but at least the wizard could generate all the base geometery.
There is also a nesting wizard, not part of the newfangled set that might work. You could use the newfangled to generate the slot code, then the nest wizard to make the array of slots.