The prequels were fairly well made as films, at least visualy and I would like to see Ridley Scott given the chance to finish what he started. But some fans, me included, thinks the prequels takes away from what the alien is. Humans created David, david creates Alien. It means the species is not only artificial, but not really truly alien either as its origins go back to humans, even if by proxy. And also the "species" is then only 20 odd years give or take by the time of Alien.