The human cost of not producing inexpensive artemisinin in vats is astronomical. If reducing the burden of malaria around the world on almost 2 billion people might harm "a few thousand" farmers, then we should make sure those farmers can make a living growing some other crop. We can solve both problems. ...Just one year of 1.3% GDP growth recovered by reducing (eliminating?) the impact of malaria would more than offset paying wormwood farmers to grow something else. There is really no argument to do anything else.
Last year, when the United States military debuted footage of an iridescent drone the size and shape of a hummingbird buzzing around a parking lot, the media throated a collective hooah! Time magazine even devoted a cover to it. Meanwhile, with no fanfare at all--despite the enormous potential to reshape modern warfare--the military issued a request for scientists to find ways to design microbes that could produce explosives for weapons. Imagine a vat of genetically engineered yeast that produces chemicals for bombs and missiles instead of beer.