This, too, is an oversimplification, and a painful example of projection. That you personally cannot imagine a sensible way to generate satisfying and distinct buttonflow to BLU does not mean that such is impossible. Even your gut image of the job seems... strange, if not outright contradictory. You say BLU is punctuative, focused on particular and effective "gimmick" casts, yet analogize BLU with BLM, a caster to which all but its highest value pure-damage cast spam are trimmed as well as possible for optimization -- almost the exact opposite; you use an infamous non-example to exemplify its core toolkit; and you imply that only one job can rightly make use of elemental spells, despite four jobs already specifically doing so in some form.
When something is given as the solution or handhold for such a solution to a given problem, it is more than a little counterintuitive to then saddle that solution with every issue it may solve. You are assuming that BLU will be integrated without making a single change in direction for the better.
If BLU were ever made an actual job, then development would have a decision to make: should the game expand to accomodate it, or should the job shrink to fit it? As BLU is not presently a real job, that point of decision has not yet been reached and the decision itself, therefore, has not yet been made. You are slipping in a premise here, and it is a dangerously pessimistic one; what you don't confront, you let pass, and by writing as if further mediocrity were only the reasonable conclusion to a pivotal decision, you condone it. I understand that precedent thus far makes that outcome the more likely, but I have to wonder if you're actually okay with it. To assume something lost beforehand, while there is still some chance and room to save or change it, is to abandon it.
I see the present extents of gameplay and each job's design's individual contribution as shallowly simple despite a surprising amount of unintuitive convolution and bloat. I do not suspect that development will see things that way, nor that they'd see eye-to-eye with almost any critic on these forums. But I do think they must at least be aware that each new job provides some amount of opportunity to do something new, and that even something of equal quality to a existent job, if providing nothing new, will be rated lower despite the equal quality. I do not expect that they will send it without hesitation to the same chopping block or cookie cutter born of previous designs. Whether they would succeed it doing something meritous with it, or ultimately somehow even worse, is anyone's guess, but I suspect it will follow the same flaws in vision or philosophy of what a job ought be more so than of templates arrived upon thus far. There will be compromise, and likely a poor result, but there will almost most likely be investigation of some sort that will change what, exactly, goes wrong.
But let us assume, however wrongly, that the developers will have both vision and an uncompromising desire to see BLU done right. Is it really so impossible? And are the few things which are obviously stupid to have in an MMO irreplaceable? Is Level 5 Death fun? Is it fun to have that serves you up to 20% of the time in leveling, one-shots every levelcap dungeon mob (as they are at 50, 60, 70, and soon to be 80), but can do absolutely nothing to bosses? Is it fun to leave that as a basic, spammable spell? Is it more fun for it either kill something entirely or not at all, on a spammable basis, than to use it as a resource spell, or even an LB, serving a chance of instant death based on "Death potency" vs. their remaining HP (to each enemy struck)?
If not, its removal has nothing to do with gutting BLU identity. It has to do with better design. Its "compromise", done well, allows for a more compelling and gameplay-integral design. Ramp up Dark element, spend it on Death in a gambit to eliminate a key but low-resistance or low-HP mob as quickly as possible so others don't have to shift off the closer targets. Likely, the roll would be placed upon a sort of normal distribution or guaranteed at over 70% and guaranteed against if under 30%. Whatever the restrictions, if it succeeds, you'll have smoothed things greatly for the run, perhaps to the point of building enough resource to guarantee it. On the other hand, if it fails, you'll have done only middling damage... and have been refunded some of the resource -- a worse outcome for sure, but hardly one worth the raid committing suicide if the roll fails. That can be entertaining and unique -- perhaps even still a "gimmick" by your definition -- but able to be included in the core game. I'd even argue it'd be far more enjoyable following the spirit of the ability, its desperate gamble, than its exact former iteration, whereby it was a dead button 80% of the time, and could break the game the remaining 20%. The "level-based uniqueness" of Death existed only in an altogether different context -- one where leveling rarely capped before the game ended unless grinding specifically for that purpose, and where combat was of the open world and comparatively dangerous trash mob encounters. The "gamble" aspect, however, survives just fine.
I can readily deconstruct the apparent issues with any of the other BLU skills just as well, though that's not to say that a best possible implementation of BLU, even without the slightest bit of compromise or conformity, will necessarily include every part of or be limited solely to past examples. Please don't confuse a particularly bad implementation with what will necessarily occur.
That's not to say I'm asking you to have faith in the development team -- quite the opposite. I'm asking you not to forgive a failure, to not assume or accept its outcome, before the axe has dropped. XIV has left a poor record, but it really does not help when people either give in -- "that just be XIV" -- or give up entirely.