All you really want is something that gives you contrast between areas of the map (and between wall/floor). Team colored dev textures are probably the most effective and easy method of doing that (they also give you information about what kind of "territory" you're in or near!).
However, they aren't necessary. See: Asteroid. Valve uses colored lighting in a few spots to create distinction between the bases, but the bases are otherwise identical in texturing (aside from any minor details that I might be overlooking). You can accomplish something similar with overlays.
EDIT: You may also consider texturing and lighting your map in a similar style to how you see it looking in a final version. The way a room or route is lit or textured can effect how people use the room (dark routes usually indicate alternate or flank routes).