I've actually commented on this in several threads over time, though I believe most frequently about tanks rather than healers. I generally enjoy the way they structure the classes within a role. For someone like me with relatively limited time to play (at least compared to years ago), knowing that every tank, for example, is going to have the same baseline set of abilities (e.g. an attack combo-sequence, a Bulwark, a larger 20% dmg reduction, an immunity, etc.) and then augment it with some unique specific skills - it makes it much more feasible to try out the different classes and see what I enjoy most. I'm confident I'll have the basic idea of what to do, and can focus my limited time on learning those specific abilities that make the class distinct.
Healers are even more varied in that regard, with the separation between "pure" healers and "shield" healers. And DPS even more so with the mix of melee, ranged, physical, magical, etc.. Heck, even within magical DPS a BLM plays very different than an RDM.
As to your question regarding perceived difficulty (we'll ignore the wild inaccuracies of your personal take on "rating" them), what developer wants to spend time creating a class that very few people will play? FFXIV of today is the WoW of 2005 (while the WoW of today has become the EQ of 2005). It's the MMO targeted most directly at casual gamers who are looking for a relaxed, fun experience playing a game. It's part of what helped WoW become the first mega-blockbuster MMO, and part of what is driving FFXIV to thrive today and continue growing with each expansion. (And heck, some of WoW's big changes like introducing different raid difficulties, LFR, etc., was in large part because such a minuscule % of the playerbase was actually engaging in the raids. It was demoralizing to put so much work into making something that so few people were actually doing.)
Because they will feel bad if the game makes them feel that they suck. So sadly we are now in a state where everyone must be made to feel competent despite their incompetence.Are you okay, Titan? I almost feel sorry for you.Sadly it isn't quite just skill ceilings that he's against. It seems that he's against anyone that is more knowledgeable than him at all.