I checked out the Northwestern program and was not too impressed. Just two shows listed: "Fly by Night" which is in association with TheatreWorks of California, and "Painted-" a project by a former Northwestern Alum. On the surface, this is rather weak effort. Plus, it does seem quite a closed program, not exactly an open Workshop for Chicago composers. Finally, I did not see any info on their web site for composers to submit their works. On the whole, for the nation's second largest city, we need much greater, and open effort if we aspire to participate competitively with New York.
Finally, I would think that a composer who believes he/she has a show which is commercial and can compete with any Broadway production, it does make more sense to begin the Workshop process in New York or California.