The fact that RDM exists, surely proves my point, though? If RDM came about as a result of the survivors of the flood of the calamity, ex-BLM and WHMs coming together and going 'damn we messed up bad', it stands to reason that the RDM, born of those two disciplines coming together, would use a combination of those two disciplines' techniques. It has Black Magics that build Black Mana with VerFire and VerThunder, and it has White Magics that build White Mana with VerStone and VerAero. Throwing the elements onto GEO and removing them from WHM, would throw things for a loop and imply that RDM is more attuned to GEO techniques than WHM, which is odd. If they wanted to fully divorce WHM from elements, they'd have to rewrite the lore of WHM, RDM, the 6th calamity (the flood, maybe it was the 5th I dont remember), etc.
Whether WHM should have been Holy Priest 2 from the getgo is not my concern, the point is that you only get one chance to make a first impression, and that counts for design too. People want their DOTs back for SMN, despite the rework, because SMN started out as having DOTs. Some people want Dark Arts and MP management back on DRK because that's how it started out.
You say 'BLM and RDM both use fire/lightning for their casting', WHM and RDM both use earth/wind for their casting. SE messed up when they made Glare. If they wanted to move towards Holy aesthetics, then they should have merged the two, elemental and 'pure light' and had like, rocks with light bursting from the cracks. Or changing the rocks to be more like the bleached white marble that Mt Gulg is made of. Instead of completely removing the rocks and changing the effect to the swishy light balls
And come on, don't do the false equivalence thing with 'X has a thing, so noone else can have it' with healing skills. Or I'll have to say 'DRG has a skill (Lance Charge) that increases their damage dealt for a duration, therefore no other DPS is allowed to have a skill that increases their damage dealt for a duration', the assertion would be ridiculous, because it'd mean deleting Raging Strikes, Trick Attack, and Riddle of Fire. You'll also remember, I've posted several times about how I'd make those healers less similar, what SE does to homogenize classes has nothing to do with me
You do have one point though: PLD and WHM both using holy magic. WHM already attacks with earth and wind, making a 'new class' as a DPS that attacks with earth and wind doesn't seem like it'd stand out at a fanfest. If I saw a class throwing rocks my mind would say 'WHM' before 'GEO' at this point. So, flip the script, and have it use the elements defensively. I'm not necessarily against GEO as a class completely, I am just against the idea of 'take aspect away from current class, make new class from it'. Like, if they were to remove the MCH's gun, and make it 100% about the tools, and then give the gun to a Musketeer class, there'd be some people who would say 'this is BS I levelled MCH for the gun wtf SE' and they'd be justified in that, even if using the tools fits more with a MCH identity or whatever. But it's a very weird situation, because WHM both has AND hasn't lost it's elemental kit. It's still using Stone IV any time you sync into SB content. It's not like the holy lightshow has completely replaced the kit at all levels, in the way SMN gets it's, 'essentially max level' rotation at level 26 or whenever you get the 3rd carbuncle.
If they really want to 'remove aspect from class, make new class from it' they have to do a damn good job of convincing me, and probably other people who hold similar thinking to me, that the removal is justified. 'We removed attacking with elements from WHM to make GEO where you attack with elements' is not enough to me. We can see like, 'we removed Noct Sect and made parts of it into an actual class called Sage', ok? Or you could have put effort into balancing Noct Sect better and not removing a whole aspect of a class from the game? 'We removed the time manipulation from AST, to make a tank where you manipulate time to reduce damage taken' has at least a little bit of potential, cos they can get creative with defensives and invuln potentially. They won't, of course, but the potential is there
I noticed this with Necromancer too. Lot of people were onboard for the idea of Necro as a job, but the moment anyone said 'what if they get wild with the design, and make it a healer', they are instantly like 'noooo Necromancer has to be a caster dps!' and I feel like it might be the same here. Saying 'OK GEO is added next, but it's a tank', and people are less enthused about it. Because they don't want GEO, they want 'Caster DPS GEO' specifically. We saw it with DNC too, nothing implied that it 'should' have been a healer, but people got angry that it wasn't one anyway. Or people who were angry that SAM was not a tank. I suppose it's w/e either way, because caster or tank or physranged it doesn't matter what GEO is, if it's ever added to the game, I probably won't be using it outside of EX roulette regardless