It probably makes sense to have so many different styles and colours of uniform, but I never got the hang of distinguishing rank/department etc with the movie-era uniforms. The Maroons were a little simpler (though I never did get my head around the rank emblems), but with the TMP uniforms you have the colour of the uniform itself (which in theory have some logic but as has been mentioned further up the thread, this logic was not always adhered to), then the background colour of the arrowhead insignia, and then the sleeve/shoulder rank indicators. It's a lot to have to check when trying to quickly identify what job/rank/department someone has. The TOS and TNG uniforms at least kept it simple.