Meh, that only happened because of how they implemented jobs.
Chances are classes will just sort of be ignored until SE decides to do a Cataclysm-style revamp of the game, which would lead to them changing the leveling experience and sort of drop classes and their respective quests. Say that in this scenario instead of starting as a lv1 Gladiator in Ul'dah, you can start as a lv1 PLD and go from there, with a lore explanation that the Gladiator's guild was absorbed by the Sultansworn and turned into a training school for them, and you'd be a random nobody that is basically being trained there. By the time you hit 30 the leader of the Sultansworn (Jenlyns) takes you under his wing, continuing the PLD questline as normal. Minor text alterations to fit this are a given.
The 3.0 WAR questline hints to this already, so I wouldn't be surprised to see some sort of changes to how classes and jobs work if not in this upcoming expansion, the one after.
The problem runs deeper than that. It involves more the core gameplay that SCH was given because of it branching off ACN without any notable changes to said gameplay. As much as some may hate me for saying it, SCH shouldn't have access to entire ACN DPS spellbook, and the SCH job crystal should have changed some of those abilities (and traits involved) to better suit a healer. SCH would end up with similar DPS potential to WHM while having more heals in its arsenal, and chances are the outlook on healing would have turned out different.