As it sits right now I think a lot of people will quickly hit a commendation before they leave the dungeon just to get it off before people leave so they can complete that weekly achievement in their challenge log.

What bothers me about this is that it devalues the entire system.

My suggestion would be to add drop-down menus to the UI for player commendations, just a simple few options with the first option being "I just want to do this before people leave" or something to that extent. Other options being "played class/job acceptably" or "social player" .etc.