Some attention to most annoying combat(or UI?) design flaws please.

[CrstyCaptin]

Agree with OP. It's really annoying, not only for tanking but other jobs too. For instance, take blm. I pop swiftcast but need to wait 1-2 for it actually 'apply' because if I start casting as soon as I hit it I actually have a cast time for my next spell. The one after that I won't have a cast time. Stuff like raging strikes should be one click right after a spell and not block me from chaining my attacks. It's almost worthless to use when it cuts down your dps so much. Doing pld right now and I find myself constantly spamming a gcd skill with the key and a non gcd skill with the mouse.

Edit: the swiftcast can probably be classified as unresponsiveness, but the other two examples work