A1. No.
A2. Never liked it to begin with. The best thing about it was how quickly it leveled chocobos, but mine was already at rank 20. Leveling, I used the job swap exploit because if I wanted to level something in open world, I have classes I could very easily spam FATEs with.
A3. No. I can do roulettes and raid on a normal job.
A4. I'm indifferent at this point. I can see it being a nifty idea and fun as a minigame as it is, but its problem is it completely lacks longevity. The process of leveling and obtaining spells was supposed to fill this void, but those are probably two of the worst ways you could draw something out. If the job were much stronger, like comparable to a level 70's damage while being at level 50, and could do more things on its own, it'd probably be really fun just because of its ridiculousness.
A5. No - why would I ever be in the open world other than for hunts? There's nothing to do in the open world.
A6. BLU could exist as a normal job, but I do understand Yoshida's worry about the acquisition of spells (learning it through monsters and not just given) and being excluded from parties because you don't have certain ones. That's a legitimate concern and players are absolutely kidding themselves if they think it's not. Some people would argue the identity of BLU is learning spells through monsters and not just given to you through job quests while others are perfectly fine with that method. Others take it a step further and compare it to XI, though it has many features that simply do not exist in XIV and is akin to comparing apples and oranges. Full job, limited job, it doesn't matter, there'd probably be just as much complaints because BLU ultimately wouldn't be something X person imagined it to be (looking at you SMN).