While I have enjoyed a lot of what ARR has to offer and look forward to even more in HW, I can't help but think about what content could be brought back from the original XIV.
I liked the original version of Behest, every hour on the hour the call goes out, you go to the appropriate level camp and join in the fun of slaughtering enemies of the realm.
Definitely would love to see some open world dungeons similar to Cassiopia Hollow, Nanawa Mines and lets not forget Shposhae and others like them...