I must say it's a little naive to think the RNG in this game (or any MMO) is truly random.

I have done 100+ dungeons (have achievement), about 70 of those are ifrit HM, not one time have I seen the weapon drop for me, in addition I have 5 other ifrit weapons that I can't use or sell. apparently the chance of not getting a 1/8 (since there are only 8 classes) roll 70 times in a row is 0.00872%, according to the accumulative binomial probability formula.

evidently, I have triggered a 0.01-% situation with a 12.5% RNG. on less statistical front, numerous people have told me they have seen the monk weapon drop few times in one day, all with not a single monk in party. I can't help but think somewhere in the code there is something deliberately making the game harder than it says it is, therefore require more play time ($$$).

likewise, your craft succession rate is certainly subject to the same "randomness", I guess the game wants to encourage you to get 100%, but by what I feel slightly shady methods.