I like to equate it to team sports. In football, basketball, hockey, certain big-time maneuvers work really well. So why don't players do them all the time?
It only wrecks suspension of belief because people view the action as turn based. Everyone is standing around while one guy goes, "Okay, my turn! Hiya!" Yeah, if you look at it that way, why can't anyone do whatever they want?
But if you see the combat as fluid, always moving, everyone always waiting for the an opening, maneuvering to get in the right spot, maybe those high intensity, high risk maneuvers aren't so easy to pull off all the time.
I like to equate it to team sports. In football, basketball, hockey, certain big-time maneuvers work really well. So why don't players do them all the time?
They try to do them all the time. But they aren't restricted by metagame rules that say they don't even have them as an option to attempt.
And yet all of the maneuvers don't work like this. Explain why a Rogue can't unleash Blinding Barrage on a continuous basis? There is no good reason, especially if his opponents happen to be unaware of him.
And who's to say the characters don't try to do them all the time? They only get them off once in a while. The rest of the time you're pulling off what you're able.
And who's to say the characters don't try to do them all the time?