I think she would have been a fascinating choice, but perhaps a bit young at 19. I think Rosemary is just as much of a shark as Finch is, just with a different end goal, and I think she's been in the secretarial trenches at WWW for a few years at least. I'm not sure that a 19 year old would exhibit the savvy that Rosemary needs. But Minnelli is a terrific actress in the right part, so who knows. She might have been brilliant.