There are a lot of maps to be created utilizing those same shaders and textures that will be awesome. The factory theme will never die, nor should it by any means. I agree that more maps should be blessed with originality and quality, however, the factory theme is okay with me. In fact, I love it. I would like to see different themes though, just for the sake of being original.
Mapping is an art form.
A form of expression that shouldn't be suppressed. The time will come when id will finish DOOM III and this process will start all over again. Until then, let nature take it's course with mappers. If I'm watching people play, I notice the maps and details. If I'm the one playing, I'm studying the layout of the map, I don't tend to notice details.