Well, to get more detailed, I would put out an information campaign to get people to a) know their rights, both customer and producer, b) recognize an illegal business, and c) know that there are people they can turn to.
I'd also have an inspection agency to inspect the conditions of the brothel, "safety equipment", and how recent the last STD check was.
The goal would be, mainly, to destigmatize it enough that people who notice something wrong are willing to come forward, instead of being too pre-occupied with "oh god i'm using a brothel" to do so. The latter is how I'd regulate brothels, with a certification a la fire-extinguishers, "Such and such months ago this premises was inspected and received an A* rating" kind of thing, with consumers and employees legally allowed to view said certification.
So it would also get rid of that idea of "renting out buildings to self-employed women" circumvention of pimping laws, as such a thing would be illegal.
I'm all for self-employment, but when the results of said self-employment are human trafficking, pimping-in-all-but-name, and other problems, I'm a little less fond of it.
I'd also allow small-time (non-living-wage level) of paying-for-sex. So if a dude gives you 50 bucks to sleep with you, one-time-deal, you aren't going to get booked for doing it outside a brothel.
The EXACT details, I don't care.
I'm not a regulator. The whole point is that it's -not that hard- to figure out how to fix shit, if you give it a few minutes thought instead of just throwing up your hands and going "I got no clue, ban it all."
AND FINALLY, it'd be very hard to get rid of human trafficking unless this was a global or near-global reform. Same with basic-income-guarantees, you have the issue of people coming to your country for the sole purpose of partaking in it, putting a strain on resources and living space. If only in terms of "Holy shit we have 5 million* people wanting to immigrate every year, how do we deal with this huge flow?!"
*Is this a lot? I don't know, Canada only has 33 million so it'd be a lot for us.