Correction, the complaints come mostly from people who've lost their "unique" buffs that no longer guaranteed them a raid spot. It'd be as if WHM, BLM and SMN suddenly got refresh. All the bandwagon Red Mages (that ruined things for the melee enthusiasts like myself) would cry their eyes out because their "unique" spell was given out.
As far as class uniqueness in the context of WoW, I had an Arms Warrior, A Ret Paladin and a Blood Death Knight during Wrath of the Lich King. All three could use two-handers and some even had similar buffs, but still felt different because despite it all, class flavor was preserved, even in the face of the so abhorred homogenization.
While entirely urinating on the people who identify their characters with one job/class more than any other. I am also one such person, as I look at my Taru in XI and think "Duelle the Red Mage", not "Duelle, the taru that can change to an underleveled PLD, a DRK that draws too much aggro when hitting things and has RDM leveled to 90". Call it lolRP if you want, but I doubt I'm alone in this.The reason FFXI and XIV can get away with pidgeonholing a bit more is because your character isnt limited by class, you're working towards one goal on one character. Being able to adjust to deal with the situation is part of the FF game's charm, and thats why the job system works so well in XI.
Either way, pigeonholing is a bad thing. It should not be spoken of as if it is an inevitable thing, as that is clearly not the case.