Hmmm. Was the DTP revolution going by the time the SE/30 was designed? And if so, was Apple aware of it?
I imagine that the Apple designers' thoughts about the SE/30 were that it would be a powerful, but basic desktop business machine, and there was little need for grayscale images in documents, reports and spreadsheets. Correct me if I'm wrong, but it was really DTP that gave a need for grayscale on the SE/30's screen.