As nice as the idea is in theory, I don't particularly like that SE assigned unique rewards to the Commendation system. It would have been better if everyone was required to give one before leaving an instance, because in my experiences, most people in PUGs/roulettes are seemingly in such a rush that they don't even bother. I've also heard (firsthand or secondhand) that some players spammed easy guildhests as soon as the system was introduced in order to hit 500 and get all the rewards, and now purposefully withhold giving commendations out in order to make their gilded mount more rare.