That prostitution should be legalised but regulated in order to protect prostitutes and clients, generate taxes, and reduce organised crime (human trafficking/drug smuggling). I am of the opinion there should be licensed brothels, which are in appropriate locations (not near schools/residential areas), have transparent and auditable accounts and charging/payment model (to protect prostitutes and clients), professional management (not controlling pimps), and adequate hygiene and safety standards (safe sex/panic buttons). Likewise, prostitutes should be licensed and undertake regular health checks and basic education in sexual health. Both brothels and prostitutes should pay taxes to cover the cost of having proper regulation. On the flip side, any unlicensed brothels or prostitutes that operate outside of the law, and importantly, their clients, should receive far harsher punishment than at present (significant fines/prison time).
We have exactly this, here in NZ. It's working well, from what I hear.