Are you really saying that everything in FFXI was bug free? Do you not recall the threads every single update "Stuff broken by update"? And there were major events broken throughout the game's history, even when stuff was brand new: Steam Cleaner not popping, Besieged ending in seconds, Absolute Virtue's buggy states, who knows if the original incarnation of Pandemonium Warden ever worked as intended. Not to mention the fact that XI events and missions only had a fraction of the complexity as the ones GW2 has. Also the cycle time on the GW2 updates has been at breakneck speeds compared to the updates FFXI had, while charging no monthly fees.
That all being said, I really wish Anet would put more priority on bug fixing, but they seem to want to really root cause the issues and strengthen the event scripting so that future events won't have the same pitfalls. At the very least when stuff was even buggier early on, they should have had periodic server resets just to temporarily fix events in bugged states.