See this is how i felt about BLU when I was starting and I had hit 75 and before Abyssea, but with the dawn of new things, I became an elitist and I would still be today if I still played the game which I have stopped playing for now until vanafest. I've yet to break 99 not because I can't, but because I see no reason to other than to do VNMS for eternity until I quit the game entirely. Yet I digress, I believed this job was capable of so much and that it could be played in any way as long as the player willed it. But the realistic thing is, jobs do things better, because they do it better they are the better selection, and because they are the better selection, means your options are limited. Unless your solo'n (in which case you can do w/e) or your in a static that focuses on the "having fun" part of the game rather than focusing on achieving great things, you are natively limited to the simple roles of DD whether that be physical or magical nuker. The bottom line is, its what we do well, not great, but we can be competitive. In all other fields, buffing, debuffing, healing, tanking, we are mediocre options (varying based on mob) I know Tashan will jump in and say BLU's can tank like a boss, because thats what he's put his mind to. But thats tash for ya lol and even than he knows better than to tank the world on his BLU.
Simply put, it isn't so much our actual effectiveness we have to worry about that makes us in the positions we can assume, it is the community. We are not a healer because the community through means of logic has deemed us unfit. Even if we were able to cure, we wouldn't compete therefore we wouldn't do it. Sure it would become an option,but a terrible one at that, to a point where you might as well have the BRD/WHM cure. You've stated I should look at the spell list, too which I fully understand the versatility and was a quality I truly admired of the job. You will also notice that not a single spell transcends the party boundary nor should it. Do we really wanna go to parties like DNCs who were so tremendously useless and have to pop off curing waltzes using TP gain atmas and gear because not many LS's let DNCs actually TP on a mob? Hell no! Thats not at all what I want this job to be, or a RDM whoring out cures (which even now it doesn't do that when SCH can do it better, and WHM pretty much dominates the two). While I understand your desire for this because I mean what BLU wouldn't love SE saying "Hey you can heal out of parties now!" or "Hey that whole timer for your spells when you swap them, f*ck that!" or "Hey you know how you can only use so many spells? PFFFTTT!! GET OUTA HERE!" I mean what BLU in their right mind wouldn't be like "FFFFFUUUUUUUUUUUUUU YAAAAAAAAAA!!!!!!" Yet that would also break game balance and mechanic, because we are so good at many things, why do we deserve the god mode button to be great at many things? Than what would be the point of other jobs that are so closely related to the tasks we desire to operate under?
Hell why don't we make every job in the game lead to BLU so this way if you want to be a tank, healer, DD, nuker, as long as you have the jobs leveled, when you play BLU you can play just like those respective jobs!? I'm not saying no to what you are asking for because I truly hate the idea, I'm saying no because I respect the other job classes out there that would have to compete with us and become void after us becoming a god. I'm saying no because it breaks game balance (what little game balance is left for elitists to even respect after Abyssea...).
I do not have a stigma for change, I full well support it, I just support it within the reason that benefits BLU, it its something neat for a niche group of vanadiel, its not worth the time supporting vs something that will support the greater good to which I have lended a hand to in discussion for improvement. This suggestion of curing outside party members ranks up there with no cool down timers after switching spells, and a JA that allows us to use all of our spells. These notions are either game breaking, defeat the notion of what BLU is, support a niche group, or are misguided in basic understandings of fundamental BLU mechanics.
The reason why subs of a BLU don't' make us back line is because BLU already can't compete with other healing jobs in healing, therefore, subbing healing jobs that get up to at most Cure IV (which ask any SCH P.S I'm a SCH, and RDM whether that means anything and they will tell you hell no and when do they get Cure V so they can actually start competing with WHM for healing positions). And as you stated we generate more enmity, so of course sub or not, we are not a healing class, we can save someone's ass, but thats it. If BLU were ever efficient enough to compete with WHM, this game would be broken and SCH and RDM would be pissed, if BLU were ever efficient enough to compete with SCH and RDM, SCH and RDM would be pissed because they are already on the shitlist for curing in groups, to only be one upped by a job that can do exactly what they do and do more, would shut out those jobs entirely (and trust me, we don't' want to give RDM's more ammo to bitch about because I still can't read a RDM thread with out hearing how DD RDM is coming! and how awesome those days will be for vanadiel!!!..... Ya... No). The fact of the matter is, we can cure just fine actually even better than fine, we cure good. We cure so good we are great for backing up when the shit hits the fan, which is great! Why should our responsibilities grow further in curing allies when we should already have more efficient jobs for that? Is being an emergency cure not good enough? And sorry but even though I'm in an ally group, if someone dies in the other party and I'm not on my SCH healing, I could give a shit less because A. Thats their fault, B. Thats their healer's fault, because if it was my job to cure em, I should of been in their party.