[5.4] 10 Man Tanking.. Mastery > Haste?

I suppose this should go here, first post for this forum but I've been lurking here for a bit. I'm looking for a specific discussion on stacking haste (not past the cap, obviously) or stacking mastery.
First of all, let me leave my armory page here. I will be changing up my glyphs and talents around for tonight as well, I am thinking about getting rid of Sacred Shield. Plus I've been neglecting to get rid of Glyph of the Battle Healer. Feel free to point out any huge problems with my gear, reforging or geming as well. I am always about bettering myself.

Now my guild is just starting on 10 man normal SoO tonight, so I have no experience in here besides with Flex, which I've done up to Sha of Pride (all that is available at this point anyway) and it always seems like I take much less damage then the other tank, as well as seeming to have really smooth damage intake, where it is all smooth, healers say it is very easy to heal me. It was the same way during my Lei Shen kill, by the end of the fight of regular taunting I took 8M less damage than the other tank. But again, he could have been doing something terribly wrong.
With this, I also have no problems keeping threat. While I don't do high dps like many of the haste paladins, I take significant less damage. This of course, is assuming they're actually doing their rotation correctly.

So my question is, should I really bother with paying upwards of 1000g to change up my reforging and gems? I really feel at this point, mastery has been very good to me and I don't really want to abandon it just to try out something which the only real reason to do so would be to increase my DPS, and as we're not going to be pursuing heroic or hitting any enrage timers.

Can anyone bring me to the light that is haste, or is it really that required?

Mastery makes your SotR stronger, but leaves the gap in between the SotRs empty. Haste instead pulls your SotRs closer to each other. Haste also has much more impact in SS, as well as more impact on EF. That it helps on damage output is a nice bonus.

Total damage intake is a poor metric to look at. It tells you nothing about burst damage. But if your healers say you're fine to heal, you should be fine, and it doesn't matter much, as long as you survive without draining healer attention.

If you do want to switch over to Haste, but don't want to invest in regemming, you could simply start using Haste gems in the new pieces of gear that you'll loot. Since 5.4 has just arrived, you'll probably replace most of your gear soon enough, so you don't need to swap gems in all the old gear that won't last you for much longer.

You should really get rid of Battle Healer asap. It's a big fat nerf to run that. Better to run with an empty glyph slot. But I see you already replaced it now. On fights where you don't want to run Focused Shield (because multiple targets), just swap to Divine Protection if the fight has little to no magic damage, or Final Wrath for extra DPS.

That is what I've been thinking, is trying it out on new gear pieces. Got shoulders tonight and really happy about that, threw what gems I had in my inventory into it.

Haste seems interesting at the very least, and I guess I owe it to try it out. Plus you're definitely right about just putting it into new pieces. But in all realism, I don't take that much burst damage, I pop a CD and I'm doing just fine, as well as my healers saying that I'm actually easier to heal then most. While my SotR is happening less often, I just time it with attacks and do fine. I suppose with going haste, you really don't have to worry about timing though because of the sheer amount of them going out.

I think there's a broader perspective than just SotR to keep in mind between mastery and haste.

Mastery:
Increases the amount SotR mitigates.
Increases the amount WoG/ET heals for.
Increases block chance.

Haste:
Increases the number of SotR.
Increases the rate SS/ET ticks.
Increases the rate SoI procs.

Between the two stats, the way that haste mitigates is smoother in principle, as it not just spreads out the mitigation of SotR, but also has our health returns and absorb ticking faster. It also maths out better. Mastery is good, but the mitigation and health returns come in bigger chunks, and block chance is still chance.

That said, both stats are close in value. One might get the impression that the difference is huge as it gets a lot of attention, but I'm guessing the difference between stacking haste vs. mastery is much smaller than the difference between optimizing the rotation vs. flubbing it up 10% of the time.

I only recently switched from gemming stamina to haste the last few weeks of ToT, and though my rotation did become noticeably faster, I didn't see any significant change in spikiness or total damage taken. My DPS did go up, which is always helpful.

Overall, Haste does slightly better on survivability, since SotR up means you're not likely to die. 45% or 55% damage reduction, they're both on the levels of shield wall. The one or the other doesn't make much of a difference. But paladins are strong, sturdy tanks. We're durable whether we stack stamina, haste or mastery. You won't notice a big difference.

You will notice a difference in damage output, though, which should make it totally worth it to switch from mastery to haste.