ok first of all i like your idea simply because you realize BLU wouldn't normally work, in XIV; there seem to be sooo many people who can't understand this.
secondly as talraen said, the number of skills you'd get is so limited, it's next to pointless.

Quote Originally Posted by Talraen View Post
The big problem with BLU in FFXIV is that the game just doesn't support the huge number of abilities a BLU would be expected to learn. Even if every ability is learned from a monster, it would pale in comparison to the total from FFXI (which everyone seems to use as the gospel of blue mages). More succinctly, given the way things have been going, blue mages would gain abilities from a whopping five (5) monsters per expansion, at maximum.

I think it's safe to say that, while this is certainly possible, and your outline does a pretty good job of making it work and keeping the flavor of BLU, it's still going to disappoint a lot of people. In my view, it's almost not worth adding BLU to XIV because it can't help but disappoint people.

However, recently I've been thinking about this and I have a counter-proposal for how BLU could work. I won't go into nearly as much depth, as I've only really thought about his conceptually, but the end result is that this BLU would be able to use abilities from every single monster in the game - temporarily.

The idea here is going to be that you learn an ability from a monster in some fashion, and can stock those abilities similar to Astrologian cards. So you can use it immediately, save it for later, or maybe get some kind of buff based on what it is. Historically, blue mages in Final Fantasy games learn abilities by either seeing them or getting hit by them, though there are exceptions (Kimahri uses Lancet to just learn them, Quistis uses items, etc.). I could see a system where killing a monster gives you an ability, but that ends up being troublesome for boss fights.

Therefore, BLU is a tank. This is a class that's all about getting hit with abilities, and tanks are the only role that actively do that. That said, even tanks don't just sit in AOEs and take them to the face if they can avoid it. Therefore, I'd suggest BLU gets some ability to mitigate or even negate one ability, which they then learn temporarily and can use. (In some ways this ends up working more like Relm's sketch than a traditional blue mage.)

I'm no game designer, so I'll leave the details to the team that hypothetically would actually implement such a system. But this would let you learn and immediately use most basic monster abilities in the game. Obviously the effects won't be as dramatic, but you could at least copy the AOE shape in many cases, and there's plenty of room to make these abilities more interesting than just animations. Maybe (taking a page from FFXI) monster type does something, so maybe all vilekin abilities have some particular effect or optional use and all wavekin have a different one. I don't know.

Or maybe this is a terrible idea! It seems like it would be interesting to me, though.
I like the idea of having something between mudras and cards, though less random than cards....but there would/should be many combos, and it would be easy to mess up, if it's like mudras....so duno.
eh maybe you could use Gold Saucer cards, or something like that, and make a "skill deck" where each card has a monster skill; that would work for any role, not just tank. there's already a hefty list of cards you can get without really playing Triple Triad.
As for bosses, they mostly use tank busters, cleaves and auto attacks - it would feel awkward to learn tank busters or cleaves, as a tank; as well as getting a nerfed version as a dps.
As a non-tank, you could have an "empathy" skill, so you tether yourself to a tank, and learn skills when they get hit (like that pld skill)
but the biggest problem and reason it won't really work, is because if BLU can use that many skills, it would overshadow all other jobs; and they want all the jobs to have a similar amount of skills. May work in 4.0, when we get more skills, though.