5% for non-Consulars, 10% for Consulars, much higher for tanks.
But still, only your melee attacks can be dodged, so accuracy really only increases the hit chance of Double/Clairvoyant Strike, Low Slash, Shadow Strike, Whirling Blow, and Spinning Strike. Low Slash and Shadow Strike are more or less Infiltration-only, and Whirling Blow is seldom used in PvP. So for non-Infiltration, you're boosting the effectiveness of two attacks, plus your basic attack. Doesn't seem to be spectacular.