Yes, they are self-imposed, and I'm all for those restrictions being broken down, but at the same time I recognise that they can't just upend the entire game overnight. Which is why they have chosen to implement Blue Mage in the way that they have.
Honestly it's a good compromise, and although doubtful perfect (I'll give my feedback once I've actually played it), it does have a lot of potential going forward, and if it proves successful enough (and the community is mature and responsible enough to handle it), who knows, maybe someday they do allow 'non-standard' jobs in to Duty Roulette / current tier Raids*.
That's not what the 'delete Limited Jobs' crowd wants though, they want their 'Blue Mage' (and all future jobs) Raid ready on day 1 'like all the other jobs', and in the current structure of FFXIV that does mean designing it 'like all the other jobs'. This is not XI (where players are used to un-balanced, niche, or outright 'useless' jobs), they can't just throw a non-standard job out there and expect anything but chaos.
Take RDM for example, a job that should be roughly 50/50 damage / healing and support, but instead it's 93% damage (due to the strict structure of XIV), and even at that ratio is considered 'mandatory' (by some) for raid progression based on 1-2 (less than 8%) of its abilities, but gets thrown out on its ear as soon as progression is over due to 'not enough DPS' (for some)... do you really expect Blue Mage (by which I mean a true jack-of-all-trades Blue Mage) to fare any better?
And yes, there are also duties, but Blue Mage isn’t excluded from duties, only auto matched duties, which you could argue is too limiting, but this is an entirely new type of job for FFXIV, and when you consider that a disturbing number of players can’t even handle the likes of low-level BLM properly can you really blame them for being cautious?
*We don't actually know if Blue Mage will forever be excluded from current tier content (which is an understandable concern), only that Blue Mage starts limited to level 50 and will have its level cap increased independent of the normal level cap, the rest is speculation based on (an admittedly bad) example of balance concerns from Yoshi P.
Good news then, there are already 15 jobs in the game for you, and more coming in 5.0, please look forward to it.
NB. That is partially sarcastic by the way, but I do feel that complaining that Blue Mage (and its content) is a waste of time because you don’t like it (and don’t see the potential) is like complaining that Savage / Ultimate is a waste of time, or that crafting and gathering is a waste of time, or that Gold Saucer is a waste of time, or even that Eureka, as bad as I personally think it is, is a total waste of time (as opposed to something that could be improved).