The unfortunate problem is that Square Enix's idea of difficulty is exactly what Jessweeee♪ has pointed out. Final Fantasy XI has never been a particularly difficult game. The game has always been an artificial time sink. A bloated experience curve isn't difficulty, it's tedium. Obnoxiously low drop rates don't make the enemies any more difficult to beat. Requiring people to repeat the same task repeatedly over long periods of time does not make the game a challenge. Final Fantasy XI certainly does have some instances of genuine challenge (finding strategies to defeat Odin in Einherjar, for example), but a majority of the content was always artificially difficult.

I don't mind a challenge. When a boss is genuinely difficult to beat but can be overcome by a specific strategy, it's exciting. When a boss is difficult and the only way to defeat him is to abuse a glitch in the game (I'm looking at you, Absolute Virtue), it's ridiculous.

Also, a lot of the difficulty in FFXI was also due to a largely ignorant player base and Square Enix's refusal to release information about the game mechanics. It took people a long time to figure out exactly how powerful haste is. Once we figured out the mechanics, the game began to descend into easy mode because, quite frankly, it was there all along.