It should be pretty clear from context, but what I meant to say was, "Who said anything about me WANTING this?" Still, it's a lot easier to try to make a weak attempt to undermine an argument by searching past posts for self-contradiction than it is by providing any sort of meaningful counterpoints of your own, isn't it?
This was a concern for me when I first started the game. Fresh out of the gates of Gridania, it took me a while to realize monsters were even USING special skills, and I only figured it out when I saw that some of the flying text damage numbers had text by them. I was thinking about BLU, even back then, and despaired that it would never work in this game simply because the mobs all had boring, damage-only attacks that barely looked any different from their standard attack animations.
Now, though, I feel that there are plenty of monster skills flashy enough that they'd go well in a BLU's arsenal. The aoe Stun used by boar mobs is a good example. Bad Breath, a BLU classic, could still work, though I'd guess it'd wind up being useless in anything outside of faceroll easy content (much like ACN's Tri-Bind).
As for mob types that only exist in advanced dungeons, bear in mind that BLU, if added, would be added in a new expansion with new areas - and Yoshi P has already stated that accessing these areas would NOT require full completion of ARR and Heavensward. There may be new low-level areas, in which BLUs could fight weaker versions of those mobs specifically to learn those skills. Even if there are no new low-level areas, there's nothing stopping SE from adding such mobs to existing low-level areas, specifically to help BLUs along. While I still doubt SE will make any kind of special learning system (and certainly not an RNG-fest like FFXI had), it's a mistake to assume that just because some skills are only present in high-level areas now, that that will always be the case!