At the moment, jobs don't gimp ANY of the classes they stem from. ALL jobs have access to their base class abilities.
Just because some people, including yourself, don't see a value in the class system does not make it broken. The reasons the class system is underused at the moment are because:
1. Most of us were level capped when the jobs were first introduced. So not only did we not unlock the jobs in a 'normal' progression, but we are all basically at cap, running events and such that typically rely on jobs>classes.
2. There is little content in game at the moment where having the ability to use your cross-class skills makes classes>jobs. Plus, because classes allow you to equip a wide variety of skills from all available classes, the class system will always be most beneficial to folks who had the time to level multiple classes vs. people who only have 1-2 classes/jobs leveled.
3. They introduced the whole 'jobs' thing a little early in my personal opinion...but nonetheless, it's here now. But it got introduced BEFORE they raised level caps. This matters because many people see that jobs are only 5 skills different (and typically nice skills) than the classes and think...well, why would I want to NOT play the job...and why is the job not really that different than the base class? I'm not arguing that there is a huge difference at the moment, but there will be as the level caps raise and content is added.
My point, is the class vs job thing, is much more layered and complicated than people give it credit for.
More directly to your point: You are worried that as we level, White Mage will "continue" to get DD spells that outshine Black Mage. I promise you, that will simply not happen. I am basing this on the fact that Black Mage got Ancient Magics for most of it's Black Mage skills thus far, while White Mage got Restorative/Buffs and 1 'use all you MP to cast it' Astral by the way, not elemental Nuke.
Basically, as White Mage grows, SE is doing exactly what you want: NOT giving it Elemental Nukes, but curative and buffing magics/skills instead. (and seriously, the remaining 3 Ancient Magics will most likely be Black Mages as well...giving Black Mage at least one spell of each element which is again, what you want. But we'll need level cap and jobs to grow more first)
White Mage use to be broken...horridly so, I will give you that. (I remember having to hit mobs with my stick in order to level...wth??!!) But it really isn't anymore. You wouldn't have so many people fighting you if they believed the Job to be broken as well. People are defending White Mage so hard because they LIKE how it works now.
As to relic, I have not gotten to that point yet, so I cant speak on that...if true, that isn't so much a WHM is OP issue as much as that portion of the relic questline wasn't properly balanced...which might have been fixed by SE if the servers weren't closed. (That whole quest I expect got some serious gameplay changes for ARR)
Even the folks who agree with you that they don't like that White Mage can outdamage a Black Mage in very specific instances, admit that in all actually, that is only against 3 types of open-world 'non boss' type mobs now. Even the 'WHM vs Moogle King Battle' is more a gimmick. It is done with 'Holy' Bombs...which cost the whm's all their MP.
So yes, in these very specific instances, due to it's survivability MORE than it's actually DD spell out put, WHM can win. (which actually comes more from it's GLA/PGL sub-class skills than WHM...sure, not knocking Regen, Protect or Stoneskin, but don't overlook the usefulness of Sentinel, Rampart and Second Wind). But I wouldn't say that they are an OP job compared to the other jobs by any sense. Being strong at a couple of things, doesn't make you Overpowered. If White Mage was still overskilling a balanced party, then yes, you'd be correct. But it really doesn't outshine any other job in normal party play....actually, if any party role came close to that, it would be the DD output of Black Mage.
And back before the jobs patch and a couple nerfs, THM's could ALSO solo this same mob. Point is, when the Devs saw both roles being able to kill Dodore solo, they fixed it. SE makes sure to keep the jobs/classes as balanced as possible. So by this logic, both White Mage and Black Mage are working as intended.
You say 'BLM is currently strong at doing ranged magic damage. (nothing else).' like that is a bad thing...like it is not enough. Black Mage is CONSISTANTLY the top DPSer in the game and has the highest spike damage potential. Period.
Also, you can solo on black mage every bit as effectively as white mage. Sure, there are some occasions where White Mage/CNJ gets lucky and finds a stone or air weak mob. But Black Mage can kill those things too, and they typically kill much faster than a White Mage so survival isn't an issue. The trick to blm is you need to kill it before it kills you.
Going back to Relics, my best friend and I farmed all our coins on black mage because of the AOE spells. Was far more efficient than White Mage OR CNJ would have been.
Again, these spells belong to a different 'chain' 'wheel' 'triangle' 'school' whatever you want to call it. Sure, Black Mage will probably see 'Quake' 'Tornado' and 'Flood' in Ancient Magics (because it IS possible to write that in lore+ it seems that that Black Mage IS in fact earning all of them), but the other spells are in the restorative school. I know you don't like it. I even understand the 'well what's a black mage going to do against a Thunder-resistant' or 'Earth-weak' mob? All I can say to that is 'trust the Dev team to create content that will be doable by Black Mages'...it might not be optimal, and you might hate that Black Mage is not the optimal DD for a battle or 2, but it happens to every other DD, and later on, we ALWAYS find ways to have Monks kill Ifrit when it use to be 'Lancer/Dragoon' only... etc.
Just as an example: IF there was an 'earth weak' boss, that boss might have multiple minions spawn that need to be slept/flared/etc. So even though Black Mages aren't the main boss DDer, people would still NEED them for the battle. Also, Monks would be the DD on an Earth Weak boss, not CNJ, not WHM. No party in their right mind would give up a curer for DDer.
I know my last sentence is what ticks you off. You think the spells are 'wasted'. I won't change your mind on that, but just because they are low damage/situational/cast by someone other than the black mage does not mean they are inherently wasted.
CNJ will get expanded nukes...I have no idea what types other than is won't be 'Ancient Magic' or at least shouldn't be. White Mage will not get any real nukes but in stead get bigger and better party buffs and heals I'm basing this on the fact that Holy is the only 'nuke' White Mage got, and it cost all their MP to cast it making it a gimmick or toy and not practical 98% of the time.
But here's the thing, both THM and Black Mage will get more nukes and abilities as well, and they will continue to out Spike Damage every other class or job.
Now, can we please end this? If your goal was to improve Black Mage, that's great. But the title of this topic will NEVER get you there. Because it started out in a bad place. 'Removing the elemental nukes from WHM' could be a point made in a 'Ideas on how to make Black Mage more fun to play' 'or Ideas to make Black Mage more engaging' etc. topic, but starting the conversation by basically implying that 'I want what those people over there have becuase it really should be mine anyway' isn't the best way to gain ideas, or have a friendly debate. Not only that, only ONE idea gets debated this way.