They should just delete AST

[Mortex]

Entirely theoretical, and only applies when protracted over a long period of time.
In a 30s window you’ll have about 14 GCD’s max, or 12 if you haven’t stacked any Speed materia.
That’s not enough time to reap the benefits of a 5% increased speed buff. Your 13th/15th GCD at the end of that 30s window will come a second or two quicker, and not even a whole GCD quicker. That’s it. You’d need to be able to fit 20 GCD’s into that window to gain one whole extra GCD, and only Ninja could do that, but that would cause clipping and therefore cancel out all benefit of it.

If it was a permanent buff throughout a fight it would make a difference.

That’s the math for every single aoe arrow. Other people even confirmed it. You either don’t want to believe math for that. I can even give you even the thread that has the math.

[Seraphor]

That’s the math for every single aoe arrow. Other people even confirmed it. You either don’t want to believe math for that. I can even give you even the thread that has the math.

Yes, I get the math, but you don't get the execution of it.
You could increase my speed by 50%, but that’s useless if I clip all my GCDs and therefore don’t reap any benefits from it. Then that theoretical, mathematically proven 50% damage buff would amount to a 0% damage buff in practice.

This is why AST cards were all just flavour.
You see it as maths and percentages, but the DPS who you're putting these cards onto are the ones who feel the effects, not you, and they don't work for them.