Some employers actually train their employees to offer a suggestion if they have a complaint.
"This place is so boring."
-- "Do you have a suggestion to make it more enjoyable?"
This is a very workable technique, although it still falls short when it's a complaint about another person. People rarely have the tool to suggest how to deal with another person, other than...
1) fix them. if that doesn't work, move to step 2
2) shame them. if that doesn't work, move to step 3
3) blame them. if that doesn't work, move to step 4
4) tell 'em to leave. if that doesn't work, move to The Work 'cause none of these steps really work ;)
If a complaint is present, people could do some work to see it's value. I also invite you to give the complainer a tool to make that value work for them...really work for them.
QUESTION FOR YOU:
Regarding the workplace, do you see managers and employees open to structured formats for communicating complaints? If so, how are complaints currently being delivered in a constructive manner?