They didn't muck it up; Forge World models are painted in a realistic style. So it's largely flat colours and a lot of chipped paint/weathering powder, etc. Their goal is to make the models look realistic - which is not something one achieves by doing detailed shading and highlighting and painting OSL or NMM.
Personally I will agree that I favour stylized paint jobs, however; the detail on models is kind of washed out by realistic paint jobs, which is a shame really considering how pretty FW stuff is.