Shadowbringers RDM Wishlist

[Archwizard]

But, wouldn't it still make more sense to just fix spell speed itself than making a horrible stat only a tiny bit less horrible compared to others in arbitrary ways, at potential cost of gameplay, to one particular job? We're on the brink of allegedly "significant combat changes to the game" as is.

... and how do you propose that? Adjusting the %-value-per-point directly for everyone -- healers and casters alike -- to address its worth to a couple instant-spamming casters? Spell speed is a straightforward stat that's a staple to most video games, and I would argue if the concern is that only BLMs stand around enough to get full mileage from it, it's not the stat's fault but the design of the casters themselves for not being able to receive of it.
Like, let's say you're right and they adjust the weight of the stat. Will a 10% value per-point increase address any of the issues you're naming? 20%? 30+? Unless it makes it some godly overpowered stat, probably not, because you're arguing the issue is in the mechanical design ("less movement the faster your GCD rolls", bearing in mind that more accurately, you're getting more casts in the same allotted amount of time the faster your GCD rolls and can more easily clip movement phases) and not the amount of speed provided itself.
I mean hell, if it didn't affect the GCD it would be garbage for anyone with instants.
Mechanical issues need mechanical fixes. At the very least there needs to be some meeting partway within the design space of the class itself.

To be honest, "at potential cost of gameplay" in this context sounds like an awful lot of doomsaying on surprisingly little to go off of.