This is why I've always pushed for ASTs to get a way to pull cards on the GCD. Allowing them to brute force them with GCDs helps mitigate bad variance and allows the player a much better shot at guaranteeing a specific card for a specific window.

Regardless, one thing to keep in mind is that AST RNG is entirely avoidable, you can just play WHM etc instead, it doesn't really cost the group much if anything anymore. Sidestepping crit RNG on DPS is going to cause a much bigger swing in your overall raid damage, potentially requiring a week or more of additional gearing to beat DPS checks.