^ this is true, though to get beyond that point, i'd say experiment with anything any everything.
people DO mix with reverb on the master, they do mix into flangers/distortion units/plugs/etc, to say nothing of compression, eq, limiting, multiband this & that, whatever.
better to know what the outcomes are and choose based on that, than to continue to produce plain-vanilla sounding/feeling stuff because you never tried anything. quite often, you really don't need anything on the master; almost equally as often, some compression can help dial the mix from good to awesome. experiment and learn.
Low Motion Records, Soul Motive, TKG, Daly City, Mercury UK