Actually, I think Hallowed is the reason that people prefer PLD over WAR for single tank situations. They don't have to care about the third Bahamut's Favor. It's much easier to survive Bahamut's Claw when another tank is there to provoke midway and split the damage.
That's not true. HG will not affect anything that's just plain intended to kill you, such as primal enrages. A particularly easy example to witness is Ramuh Extreme's Shock Strike. Even if you have Surge Protection, you'll still take damage from it while HG is up.
Ever since the 2.1 changes, there's one thing that the WAR has always been better at than PLD: Mitigating predictable burst damage. Why? Because Inner Beast has the lowest cooldown of any damage reducing attack in the entire game and a WAR who is actually good at their job can have it up to reduce every spike when they're predictable. Our burst damage attacks in Turn 9 are Ravensbeak and Bahamut's Claw. They are predictable. They are more predictable than Death Sentence, and Inner Beast can be up for them. Every time. If a WAR is getting instagibbed by these attacks and it seems odd that it's happening, it's just a bad tank. You wanna survive the third Bahamut's Favor without HG or Holmgang? Stack Inner Beast and Vengeance. You're now taking 56% damage. You can even use Storm's Path for every one, although I'm not positive how that affects the math. Even if you don't have Vengeance up, WARs have the distinct advantage of never running out of cooldowns when faced with predictable spike damage.
I also heard the "Paladin's can reduce a hit to 40% of its original total." That 40% number comes from a Pally who stacks Shield Oath, Rampart, and Sentinel at the same time. This is something a PLD should never, ever do. For lulz, it looks like the lowest a PLD can get to is about 23% if they have all of those cooldowns up and successfully block with the Noct Shield.