One of the things I hear a lot from other tanks (especially paladin tanks) is how much they envy Charge, and especially being able to Charge in combat. "Man, I'd give up X for Charge." Usually what they want to give up is their shield throw, or their AoE taunt, which of course is not a terribly compelling idea: warriors have parallels for these abilities and charge isn't one of them. Heroic Throw is our weaker form of Avenger's Shield and Challenging Shout is our stronger but longer cooldown AoE taunt. As soon as they gave up Righteous Defense (which rocks on the Lich King fight, btw) they'd just say "Man, I'd give up X for Challenging Shout" anyway. If warriors actually managed to give up Shockwave for Consecration they'd want it back in a week.
What it ultimately comes down to is the difference between a necessary ability and one that is useful but not necessary. You also need to take iconic roles into account. I doubt many would support giving warriors Blessing of Kings, Blessing of Sanctuary, Lay on Hands, the paladin system of Auras, or what have you. The ability to die without taking equipment damage via Divine Intervention? How much, exactly, is Charge worth and if it's so pivotal to tanking why are you rolling a paladin to tank instead of a warrior? How do we keep classes compelling and interesting while giving them the tools to do the same job?