The problem with "Instant OFF GCD" abilities makes combat feel less rewarding.

[Furio]

Completely agree.

Combat is utter crap as it is.

And Vahn, source please.

This game does have non GCD abilities that are intented to be used reactively. Why else keep them OFF the gcd? So no, it's not working as intended.

The system is broken, period. You can't even do your regular rotation in the fear your stun won't register on time (Paladins on Ifrit HM for example).

Really, did you even see the videos posted by the OP? It's obvious.