I have no problem whatsoever with the 5 minute restriction.

From my own personal experience I get 4-5 hours of gameplay a night. So if all I wanted to do is Dungeons (completely ignoring Companies and Settlements) then I "may" get in 2-3 full completed dungeon runs a night (keep in mind the timelimit is an hour). So for the higher rank dungeon I'll be going in with 8 different people. That means the treasure IF it drops, and IF I can use it on my class, and IF i'm next in line for that treasure would have to go 8 different ways. Don't forget there are 8 different battle classes, and there could be gear for each one of them. Don't forget that there are multiple equipment slots, and there could be dungeon gear for each slot. (weapon,feet,hands etc.) you start to multiple that by 8 jobs and all of a sudden you could look at a quite large gear pool. Now also couple that with the fact that the drop rate for some of this gear could be quite bad (think on the small NM drop rate being 10% sometimes).

With all that said, are people really concerned with being "done" with this content within a few weeks? Do the math. I don't see it happening.