I wonder if this would perhaps make things worse for illegal prostitution.
We pretty much know that legalizing prostitution will not get rid of the problem with the human trafficking and the exploitation. However with a legal industry, a large number of customers would prefer to visit the legal and safe brothels. The problem comes in when one regulates and taxes something the price increases, probably not so much of an issue, but in effect that will mean that the only way for illegal places to compete would be to offer a much cheaper and much riskier service.
For the poor women trapped in prostitution this would be disastrous. I wouldn't be surprised if their life expectancy dropped by half at least. The up side is that hopefully the lower income and decreased demand for illegal services will lower the rates of human trafficking abductions and other horrible crimes that supply them.
I think legalizing prostitution is the best course of action, but with that in mind give a thought for the "suck for a buck" women.