A few of the people I know that mentioned something like that you're responded to also laid out / referenced ways to fix these issues though - they havent (not all) simply left the issues where they lie. Some have been asking for the more extreme version but the people I see most frequently are not.
Issue 1: Blue Mage joins a group with 1 skill.
Solution: Don't let Blue Mage join duty finder without the skills that work for the related content. In fact consider that for all jobs, not just Blue Mage (no more level 50 conjurers or people that are 5 job quests behind, although to be honest at least to me it's a rare occurrence lol).
Issue 2: Blue Mage has way too many skills to balance.
Solution: Don't try to balance all of them, select a subset that are balanced for both gameplay fun and fairness. To be clear I'm not suggesting the blue mage book needs to be removed, I'm talking about the duty finder side. The party finder / solo side can hold the other 100 skills lol.
Issue 3: Blue Mage has to learn their skills they're all about learning skills.
Solution: .. ... Let them learn their skills, because of solution 1 we'll have no problem. In fact in the long run blue mage may be cheaper to maintain. Each job getting a quest every 5 levels (or more) that has to be made up in lore, scripted, and then translated into many languages meanwhile blue mage is taking assets already in the game and needs no job quest except if SE wants to add one just because.
Issue 4: Blue Mage is all about customization! It's about the loadout!
Disagreement: Only in FFXI really, for the most part all jobs in all the games have had silly amounts of abilities and this is not special to blue mage (and abilities that do incredibly silly things, death is regularly a black mage spell too). Also if you consider learning "customization" then I'd also say many variants of FF had learning of skills via items, materia, scrolls, and what have you. So I don't think customized loadout is particularly a Blue Mage thing, and if their duty finder version couldn't be customized I would disagree with someone that suggested that's not very blue mage. Although, I am not against the customization in the old content (as SE plans blue mage currently) - could be fun for sure I just don't think you lose any substantial bit of blue mage by not having it either.
Issue 5: Some of the spells are OP
Solution: Like sleep on black mage in the context that would be OP don't let them work so OP like (sleep doesn't sleep bosses). For example Death is a single target hallowed ground cooldown spell that will deal lethal damage to any non-boss related monster, boss related monsters will take 500 potency and a mortality debuff increasing damage to them for the next 10 seconds.
Or
Solution: Don't let the spells that work in duty finder be the crazy OP ones, let them be the spells that work in party finder.
Issue 6: So there is a set of skills that work in duty finder and a set of skills for party finder / not current content? How to manage?
Solution: Flip-able job stone (dual stone in essence), this will manage your gear, skills that can be put on the bar, the bar itself, and how the party finder / duty finder reads you (such that you can't fool the duty finder with your unbalanced set, it's easy to manage, and people in party finder know if you can do current content or if you're going in OP mode with restrictions on what content).
Issue 7: But I want that sweet solo content / casual aspect SE was selling, don't ask them to remove it!
Solutio--: Very few have asked for a pure purge (or any) of that side of Blue Mage. I've seen some but at least to me most are either uninterested but not wanting to damage content for others or want both (like myself).
Issue 8: It costs money and time!
/shrug, that's true and there is little I can say besides ask for it anyways. Like SE says preventing chocobo from messing with your duty queue is too hard, but people never stopped asking for it (and a long, long, while later it works lol). They found a way. It's true some things are just too dang expensive to do, but I don't feel blue mage is extreme (but is definitely time and money consuming without a doubt).
But I want to say they already have designed 100+ skills for blue (we will start at release with 48). Out of the 100+ they have planned I'm sure they can narrow down a selection of 24 that they can then tweak into a cohesive gameplay unit that is fun and fair. They already have the skill art, animations, and means of acquisition, thus Blue Mage becoming duty able is a cheaper job than just making a fresh job at least.
I don't really have a solution though, money and time are not limitless (wish they were, Yoshi if I had a lamp to rub for that I'd do it so you can make some instanced houses lol :3 <3).
Issue 9: Yoshi-P doesn't want to.
He's changed his mind before, but indeed another thing I can't do much about besides hope it'll change.
I think a lot of the better "probably not going to happen guys" arguments are being based off issue 8 and 9, because what can you do?
I'm looking forward to trying the solo/party finder version of Blue Mage, hoping it has some broken skills for party finder/solo content, and from the system I'd like to come back to this thread with a vague example with their current system how they might move Blue Mage into duty accepted status. So we'll see there lol.
Majority of the issues to me seem rather benign in that the solutions begin to reveal themselves in just casual discussion and are not uniquely terrible costs (unless you're suggesting 100+ balanced skills, which I'm not lol).
Lack of desire, money, or time.. those issues are much harder to deal with and I feel in the end those are the real reasons why Blue is as it is - I hope we can convince them to give players that casual solo / party finder side of Blue Mage and also add the duty finder main core. I also hope they consider to do the same to any other job. Perhaps next time they can start beast master off in the solo / party finder side but then work him in slowly after fleshing out the beast master's systems - this could be the new thing. I'd be okay if they started every "unlimited" / "advanced job" off as "limited" with a longer term plan to flesh out their interesting bits first (even if that's a many month project).