I'm pretty sure everyone enjoyed doing it then why not make it like a good source of obtaining xmog equipment for example by defeating the given encounters? the old challenge mode items from pandaria / wod are not obtainable then perhaps its a good way to bring them back? not necessarily the exact same items though, just an example of what the rewards could be. Brawling arena was really fun early xpac when people gathered even the low levels who cheered and laughed to people and it was a really nice casual experience for me at least.