Well, as mentioned, security officers got body armor and helmets in TMP and they were seen wearing it later on in TWOK and TSFS. I've read some opinions that it looked silly or maybe folks just didn't like it. What can you do? Can't please all the people all of the time.
Incidentally, the movies brought about many such changes. Security uniforms included armor and helmets, engineering uniforms included rad suits and protection, landing parties got jackets, and so on.
Once TNG era started, it went back to one type of uniform for all crewmembers, no matter the duty station or posting.
I know, movie versus TV budget and all that. But still.