The issue is the current best items in the game is based on luck. The best items in the game should never be based on luck. Like Fusional said pages ago there is an issue when a hardcore player does hundreds of runs and doesn't get an item and then the casual player does 20 and gets it then there is a massive issue.
Such low percentages are just an awful idea, any percentage drop below 10% is insane to be honest. Like Sol said there needs to be a balance between amount of times able to complete a dungeons and the drop rate. The difference between this game and FFXI is that FFXI had 18 people in a party and the time restrictions made it so getting items took forever. In FFXIV with only 8 people in a party you can use the same restrictions and gear up everyone completely in less than half the time it would have taken in FFXI.
The thing is nobody wants to fight the same thing hundreds of times just to not get the drop they want. It's not fun, and it makes the originally fun content boring due to excessive repetition. To be honest they should just tokenize all of their content if they really want this ridiculously low drop rate.
@Lux: You do not understand statistics through repetition.