I didn't start maining WAR seriously until after 2.1 when most of the changes were made, so I cannot comment on the amount of HP restored by the ability. However, what it also has tacked onto it is a six second, 20% damage reduction. Which is very handy, but only if it is timed properly (i.e. when tanking in T5).
I still feel like many Warriors aren't able to fulfill their roles as "Reactive Tanks" in this game as well as Paladins can fulfill their roles as "Proactive Tanks".
Every healing ability a Warrior has (Other than Inner Beast powered up with Berserk, which can only be done once every 90 seconds and doesn't even stack up when compared with a regular Cure spell) can be completely dwarfed by a single tick of Regen. Even an entire duration of Bloodbath and wailing on the opponent like mad can't heal nearly as much as is needed. A large issue is that the heals are directly based on damage dealt, much like a Blood Sword, when instead there should be some percentile bonuses to the damage healed based on Max HP.
Taking a closer look at the differences between PLD and WAR abilities, it is pretty clear to me that Defiance has two crippling aspects as opposed to Shield Oath:
1. It has a 5% higher damage dealt debuff than Shield Oath. I'd be more than willing to take a 5% cut to HP if it meant getting 5% more damage each turn, especially since that is what Warriors are built for.
2. Every stack of wrath grants a 2% Crit Chance. Even at max stacks (which don't last long anyway), this is only a 10% increase. I'd rather have a flat 10% damage boost.
Then there are the class-specific temp buffs.
Warrior gets, as exclusive buffs that a Paladin cannot use, Berserk, Thrill of Battle, and Vengeance.
Paladin gets, as exclusive buffs that a Warrior cannot use, Rampart, Fight or Flight, Sentinel, Tempered Will, and Bulwark.
Not only does Paladin have more abilities than Warrior does, and not only do Paladins get more useful cross-class abilities (Foresight and Bloodbath come to mind, especially Foresight), while Warrior gets the short end of the stick (Provoke is great, Awareness is stupid, and Flash isn't desperately needed, considering Warriors already have at least one AoE Aggro generator by that point) but they also get a buff that grants a 30% increase in damage, something far more suited to a Warrior. But since Warriors already have Berserk, which is also a damage increase buff, let's compare the two abilities:
Fight or Flight: Increases damage by 30% for 20 seconds (30 second duration with the trait)
Berserk: Increases damage by 50% for 15 seconds, with a 5 second Pacification placed on the user when Berserk ends. (20 second duration with the trait)
The extra 20% damage is nice, but for a job that is meant to be healing and extending its own HP as much as possible due to lack of defensive buffs, Warriors really should have something more lucrative and without drawback. I'd be willing, as a Warrior, to take a 10% damage cut on Berserk just to ditch the Pacification that follows. Either that, or I'd want Fight or Flight to be a Cross Class ability for Warriors, especially considering that Paladins can already take a Marauder's Foresight.
I should also remark on each one's cross-class abilities from other jobs.
Namely, the usefulness of Second Wind on Warriors vs. Protect/Stoneskin on Paladins. First and foremost, I should ask why Second Wind is based off physical attack power rather than Max HP. For something meant to be an emergency cooldown ability, its healing ability is rather inadequate. I find a single Regen tick heals for about 150% more, even with Convalescence. On the other hand, Protect and Stoneskin are universally helpful on Paladins, who have many opportunities in any given battle to cast and give healers a breather.
Sorry for turning your post into a rant. At first, I was just looking for info on how Inner Beast got nerfed, then I decided to compare abilities between Warrior and Paladin, which just kinda started setting me off at how inadequate one job is at doing its job of taking heavy damage and healing it back in an adequate amount and having a lot of pretty rubbish cross-class abilities that almost never see any use whatsoever (Provoke is really the only good one), versus a job that gets a ton of relevant buffs not only from itself, but from each of its cross-classes (Foresight, Protect, Stoneskin, and Bloodbath are all useful to a Paladin).