I like the idea of a defensive stance, but I'm not too keen on locking you out of your abilities. As stated by Hoshikogi, it would be an "Oh snap!" skill, which we already have in the form of Hallowed Ground.

Rather, I'd like to see them bring back the "Block" ability, where you raised your shield and could still use abilities. The trade off would be disabling auto-attack and hindering your TP generation.

In this block stance, we could have increased Phalanx damage, maybe a more potent shield bash, but a reduction in sword based WS potency.

There are plenty of options to go about something like this, but locking us out of our skills isn't a good idea I think, especially with trigger happy mages lingering around.