First, no change will bring us down to zero intake. So if the expectation is that there's a quick fix to cure all of the problems, jettison that idea.
Imposing a visa has a direct effect in reducing refugee intake. Look at Mexico. Look at our friends in Europe. However, did that stop the flow? No. It reduced it, but at what cost? Diplomatically, we take a shot to the head by doing that. It runs counter to our obligation to provide a freer flow of goods and services. You have to balance the cost of saving pennies on the refugee determination side with the risk of having poorly or unsatisfactorily identified individuals among us.