This ability will not remove the Daze effect caused by running from mobs, or a hunter's Concussive Shot effect.
In Warsong Gulch, when protecting the flag carrier, take note of the number of enemy priests or shaman around before casting Blessing of Freedom. They can easily dispel it. Also, a level 70 mage can spellsteal it.
As Blessing of Freedom only lasts up to a maximum of 14 seconds, the casting Paladin should make sure they re-apply a Blessing with a 10/30 minute duration afterwards.
Patch 1.6.0 (12-Jul-2005): Will now counter the movement impairing effects of Frostbolt, Cone of Cold, Frost Shock. It will no longer prevent the damage taken by Frost Nova, Hamstring, Wing Clip, Mind Flay, Counterattack, or Blast Wave or the melee and ranged attack speed slowing effects of Cripple.