chrishuyen said: "The discussion in the Here We Are thread got me thinking, what's the most prominent/well-regarded musical that has never been on Broadway? I'm not talking things like Assassins or Little Shop which did eventually make it to Broadway in a revival, but things that have firmly stayed off-Broadway/regional and still manage to be significant today.
For the sake of the question, I'm considering mostly American shows, since there's a whole slew of West End/other European shows that have never made the transfer, but I think one that comes to mind for me is Hunchback of Notre Dame."
I guess it depends on the use of the word significant - but FANTASTICKS, LSOH, NUNSENSE, FORBIDDEN BROADWAY, ALTAR BOYZ, NAKED BOYS SINGING, like them or not, have proved to be the most successful Off-Broadway and have all had touring productions our separate non-replica productions. I think the meat and bones of your question is which ones have artistic merit, have had success other places, but not made it to Broadway, TICK TICK BOOM, DOGFIGHT, TL5Y (and some might argue SONGS FOR A NEW WORLD). I personally like ZOMBIE PROM and RUTHLESS a lot too, which were pretty well received during their time IIRC.