It seems we have two differant situations at hand.
Situation1: Low drop rate but spamable dungeon.
Situation2: High drop rate but cooldown.
Most of us know Situation 2 was the system in FFXI. A great game that was successful for many many years.
When looking at situation 1 you can see right away that the ability to pick up the game and grab a party for Endgame at anytime you want is more focused for Casual players. Which is what SE wanted with FFXIV.
When looking at Situation 2 you see that it would have to be more of a planned scheduled event that has to take presence over RL if you want to atend the event. Not for the Casual players.
It looks like Situation 1 is what FFXIV is going to be...
The only thing you can hope for is that SE decides to add Both situations in the game to cater for all kinds of players.