So I ran my five Timewalkers over yesterday and today, mainly as a way to get a sense of the new Protection and of course, as always, a desire to get that damned Infinite Timereaver mount, which MUST BE MINE. (If you've read this blog a lot you'll know I'm kind of obsessed with the Infinite Dragonflight.)
We are definitely squishier than we used to be. Partially this is because Light of the Protector is designed to be more rotational than Word of Glory was. WoG was more about saving it at five stacks of Bastion of Glory to more or less be able to Lay on Hands every fifteen seconds or so. Light of the Protector doesn't get any stacking buffs and is, by the nature of its design, a weaker heal.
I think we're designed to not be at full health very often, and Light of the Protector gets more powerful the lower on health you are. It's still not terribly strong when you're low - I believe it might be affected by some stats, because on the PTR mine said it healed for 34% and on live it's 33% of the missing health (I have Consecrated Hammer, so it's always got the bonus healing on it.)
Shield of the Righteous is also definitely not going to be up as often. The one or two second speed-up on its recharge from Judgment does add up, to be sure, but the fact is that you're not going to be able to keep it up as much of the time as you did before, which means sometimes you're just going to have to hope you block things. Once we get back into questing greens it's going to be even worse, but as we get more haste things should improve again. You still want to use it rotationally (don't let the 3 charges cap) but you can hover comfortably with one or two charges to make sure you have something for when there's a big attack.
Ardent Defender I think is playing a similar role that Divine Protection used to play, and you should probably use it liberally, as it has a pretty short cooldown.
But for the most part, you're going to need to rely on good healing. The last dungeon I tanked was Shattered Halls with a Druid healer who cast Regrowth and only Regrowth. You have lots of tools at your disposal, but you aren't going to be able to totally compensate for an incompetent healer. Thankfully I have the heirloom trinket from Mythic Dungeons that gives an enormous absorption shield on a pretty short cooldown, but even with that I managed to die on Kargath once.
Threat and Damage:
The good news is that threat and damage has not been nerfed, and if anything, it has been buffed. You don't have Holy Wrath or Hammer of Wrath anymore (though Hammer of Wrath was never really that necessary for Prot - generally when an enemy was that low you didn't need to work hard for threat anymore.)
One major thing I will say is that if you don't have Consecrated Hammer, you're going to have to fight a bit more for threat. Without that, Consecration is your only real AoE move, and Hammer of the Righteous does not AoE unless you're standing in it. That's usually fine, but if you just threw down your Consecrate and then a party member pulls some other group of adds through a path that does not run through it, you're going to have to hope that Avenger's Shield is off cooldown and there are three or fewer adds to pick up.
With the talent, you just run up to them and Hammer of the Righteous (if you picked Blessed Hammer, that'll work too.)
One of the really odd changes is that Hammer of the Righteous (which takes the place of Crusader Strike as well) has gone from being a high-priority "always on cooldown" ability to one that actually takes the back seat to what used to be "fillers." Consecration is hugely important, though somewhat less so if you take Consecrated Hammer, as without the talent it buffs Shield of the Righteous, Light of the Protector, and gives Hammer of the Righteous its AoE damage. Judgment is also hugely important because it speeds up the cooldown of Shield of the Righteous. Avenger's Shield maybe takes a back seat to those guys for survivability, but it's a huge amount of threat.
You also now have Avenging Wrath again, which can be a big boost to damage but also, of course, one for healing. That means a buff to your Light of the Protector, which could sure use it.
With Glyph of the Consecrator gone, your mobility while tanking has gone poof. That said, you do have Divine Steed now, which is on a one-minute cooldown and increases your speed by 100% for something like three seconds. It does let you briefly fight from the back of your Charger (or whatever your racial Paladin mount is,) which is cool, but mostly is just a way to get quickly to where you need to go. Still, Consecration is going to stay where it is. It's a decent radius, but it does mean you'll have to be careful with your positioning.