I've stated this before on a similar thread. The script MR saw when she turned it down was a lot different than the finished product audiences saw. It was a little disturbing--and probably closer to what a real prostituted woman would experience (which, by the way, was the reason the film Whore starring Teresa Russell was made--to show that that life is anything BUT the fairy tale PW turned out to be.
How different was it? Willem Dafoe was considered for the male lead. That being said, I remember another actress saying she was glad she didn't do that part, saying something to the effect of, "Good for her [Roberts], but I saw it as glamorizing prostitution, and am couldn't see myself playing that character."
I don't know if that was MW's reason, but I'll bet it was a conscious decision an not a mistake.
Molly was offered the film well in advance of what it wound up becoming, which was a toothless Garry Marshall rom-com. The script had been kicking around for a few years under its original name, 3000, and was a much grittier drama about a whore who was bought for a week by a high powered businessman who made a bunch of promises, then dumped her ass back on the street to find another customer. So back in 87/88, Molly's star was still quite bright and she would have been considered a get.
I never understood this logic. The roles are also made BY the actresses, just switching them out wouldn't have had the same turn out. She could have accepted both roles and ruined both movies and they would be in the .99 cent bins and no one want them.
--------------- Hey Laser Lips Yo Momma Was A Snow Blower - Johnny 5
Molly Ringwald would have been all wrong in the version of Pretty Woman that got made, I doubt they would have cast her, and I also kind of doubt they would do much casting for whatever the tougher, grittier version of this film was at one time if it wasn't actually closer to production.