Box office aside, did those shows work or not, artistically speaking, in their Broadway houses? The ones I saw that were done well most definitely did.
What we really have are two questions:
Will the show have a Broadway sized audience?
Will the show work in a Broadway sized space?
The first question is always a valid question. The latter is one I always have trouble with. If one person shows and intimate plays can work in a Broadway house, why can't intimate musicals? Of course, they can work in a small Broadway house. There's no suggestion that Yank would play the Gershwin if it were available. Of course, Yank could fit in a Broadway house. I believe any show can.
The question for any show is whether the show is done well and has the audience to justify the huge risk of mounting and running a Broadway show..