Starting from page 1 boysss:
Yeah, they're all viable, but are worse or better, depending on your skill level and, to some extent, gear.
I'd say blood is the most difficult spec to properly play out of all 3 since you don't get as many passive damage reduction talents but what you get is insanely good self-healing and some defensive abilities which take you knowing your limits into consideration (WotN/Rune Tap).
Frost is the most generic tank spec out of all 3 and it is extremely good for new players. It has tools to reduce damage taken passively at all times (Improved Frost Presence, Acclimation) while having insanely high threat numbers+longer defensives.
UH is also okay for new players but it isn't as good as frost on this patch anymore. Managing Bone Shield in ICC/RS is much harder since it usually lasts for just a little while, but you do have AMZ (useful for 1 damaging spell absorption) and better magic damage mitigation via AMS (I'd argue that frost still has better passive spell damage mitigation due to potentially getting up to 150 bonus resistance of specific school).
Poor comparison, only 1 raid and it's RS - a raid where Corporeality can literally mess up stats in a matter of seconds. If you want to show stats which are actually reliable, do it on a boss which has consistent damage and it doesn't get increased in any way during the fight (Lord Marrowgar in ICC for example).
Lichborne is irrelevant when it comes to the very end-game of Wrath. Death Coil healing is not going to save you from that 15-40k hit (depending on boss). The ability itself is only useful up to ToGC patch. Anything after that, Lichborne is more of a bait for RP since it eats at least 20 RP (with glyph) and has a decently long GCD when in frost presence.
Desecration is a whole different story and is in fact useful for certain PVE encounters like Jaraxxus, Champions, Anub'arak, LDW, DBS, VDW, LK, General Zarithrian, Halion hc.
Shamblings can no longer be slowed nor frozen with Hungering Cold. They can still be stunned, which is why I'd recommend paladin, protection warrior over DK or druid on SR at this point.
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My own recommendations would be:
If you're new to this class in general, play Frost tank. Insane threat numbers+somewhat typical tank spec with good defensive abilities uptime and also doesn't require you to manage your defensives too much.
If you're not new to this game but still trying to learn, stick with Frost for your main raids and start slowly experimenting with Blood/UH specs. Only by doing your own research and applying your own mechanics to a certain spec can you learn what's the best for you.
If you're a high tier end-game raider, you should already know what spec is by far the best for you and why.
I strongly advise against going Blood or Unholy if you're a new player who doesn't know much about the raid+class mechanics. These specs, while they might seem strong, are only actually good when you understand at least the very basics of the encounter you're doing and the way this world works in general. Blood, much like Unholy, relies on good timing of defensive abilities which is why it is much more complex for newbies to pick up.