Frankly I dont see why they have not done this beforehand. Its simple math...
Paladin takes 0.8x Damage, = 1.25x EHP and 1.25x Healing Received.
Therefore, Warrior takes 1.0x Damage, and has a stance that gives them 25% more HP AND 25% more Healing Received.

Once that it done, get rid of the healing mod on Wrath stacks, and make Wrath just give a little extra dps if you choose to keep the stacks, or enable you to use "useful" abilities if you spend the stacks.

As PiedPiper said, Paladins reduce damage before it happens, while Warriors recover from damage faster after its been dealt. In the end, the amount of healing for each should be identical.
The difference... yes, there will be a difference... is that War can parry, Pally can block and parry. War has higher aoe dps and stronger aoe aggro, Pally has almost no aoe dps, weaker aoe aggro, but slightly stronger ST aggro. War's defensive mechanics center around self healing and smaller defensive cooldowns. Pally's defensive mechanics center around larger defensive cooldowns, and pretty much no self healing... lol 200 point Cure.