Sorry, didn't have time to read through all the arguments.
The problem I see with 5 min buffs is not the casting every 5 mins. It's the getting a party of people to stand still in a cluster every 5 mins and not just run to the next mob. Even during combat parties spread out due to ranges and positioning for optimized damage and defending. With 30 min buffs like we've seen in XI and many other MMOs, it is much easier to get people gathered once in a while vs every few mins. The 5 min buff would have worked better in XI anyway due to the nature of camping and use of a puller. But the very nature of XIV is for the party to be mobile and just the organization of getting everyone to move in the same direction can be quite challenging as it is, ha ha.

Cheers