Reading those slight details about the Deathwing encounter, IE, riding on his back, made me think that a portion of the encounter might involved tearing off his vaunted armor that the Goblins have continuously repaired over Warcraft's history.

Possibly, possibly not. We know the Deathwing encounter starts in Wyrmrest Temple, but getting to Wyrmrest from Stormwind/Orgrimmar is a pain even with HGWT and I can't see them forcing raiders to either make the trek, bring a Mage or rebind hearthstones there.

Speculatively, they might have us attack Deathwing's citadel but the bosses delay us while Deathwing gets away. Then an NPC shows up with the usual "NPC X is at location Y! Quickly, heroes, step through this portal!" spiel, and off we go. That's pure speculation though, based on nothing more than knowing that unless they adjust the tier drop system, they'll need at least five encounters for the heroic pieces to drop from. Even then, the Deathwing encounter could have five phases and drop loot after each.

I'd say the Deathwing fights will be the respective "wing end boss" (which then of course drop the tier tokens) with some other bosses scattered inbetween. The Twilight Father is a too good option to leave him out of this.

We also know that Deathwing's raid will less encounters then Ulduar, which was 14 bosses. I'm expecting about 11-13 bosses here. Deathwing doesn't have enough body parts to fit all that.

Good chance we may see Chromatus in this raid, his introduction and the fact he survived is suspicious.

A bit of a late response from my side but a blogpost (Warrior Tier 13 and Visual Retrospective - World of Warcraft) about the T13 warrior and warlock sets said that we'll be taking on "Deathwing and his minions" so there will probably be both trash and other bosses then Deathwing.

The Warlock tier set also hints that we wil face an old god minion with N'Zoth being the 'guy who signs deathwing's paychecks' it kind of makes sense for them to be involved in this raid even if it isn't the old god (who should have it's own raid in the next expansion).

Twilight Father and Chromatus look nailed on to be raid bosses would be a shame to waste them on 5 mans (Chromatus has potential as a highly complicated encounter with 5 heads with powers of each aspect).

I think Blizzard would be too afraid of the reaction if they didn't have some sort of lair for deathwing populated by minions, given that they have often been accused of being lazy and cutting corners throughout cataclysm, I think they will feel pressured to go all out with the final raid. I predict we will fight through some sort of twilight installation combating a number of twilight dragons, some cultists, a few black dragons and some old god minions possibly interspersed with Deathwing encounters before being portalled to Wyrmrest by Alex or Kalec to help repell Deathwing's attack

Would be nice to see Magetha again. It's about time she shows up again.

Doesn't mean though that the Old Gods didn't get a hold of her. The Twilight's Hammer is, while the largest, only one of the organisations working for the Old Gods.

OK an intervew with Ghostcrawler ha just gone up with some details of 4.3

The Deathwing Raid - dubbed 'The Dragon Soul' will have 8 bosses with boss 7 and 8 both being deathwing. Fight 7 sees us parachute onto his back from a gunship and peeling back the armour on his body then fighting the corrupted blood adds that come out of him. Fight 8 sees us fighting him at the maelstrom jumping from island to island while fighting tentacles and activating the other 4 aspects to unleash special abilities (maybe like the blue dragons in KJ?).

New legendary is 2 daggers for rogues, questline is from the black prince who will hatch from the uncorrupted egg in the badlands. This prince is the only uncorrupted black dragon but he is not exactly a good guy and is out for himself - potential new aspect here.

The first new 5-man is called "Endtime" where Nozdormu will show players the future if Deathwing wins - The Hour of Twilight in essence.
The second new 5-man, "Well of Eternity" is a journey into the past, the War of the Ancients specifically, to help Thrall recover the Dragon Soul to use against Deathwing.
The third new 5-man, called "Hour of Twilight", has players escorting Thrall in present day to Wyrmrest Temple, where the final battle against Deathwing will take place.

This all sounds very exciting in my opinion.

I just hope Thrall has a faster horse when we're escorting him to Wyrmrest Temple!

GC mentions that we'll fight one of Deathwing's tentacle in the Maelstrom fight. I think we rip out all his plates when we're on his back hoping that his fires will consume him from the inside out but instead these writhing tentacles burst out of him. It'll be interesting if that's actually the case, since it gives us an Old God flavour for this expansion (and let's be honest, an expansion based on Azeroth not having an Old-God inspired raid encounter feels a bit wrong) and gives us a glimpse into who is behind Deathwing (N'zoth?) so we can deal with him in the next expansion.

I find it very interesting that the uncorrupted black dragon isn't under the tutelage of any of the other dragonflights but is instead forging his own path through the world. Neltharion was described as being very analytical and one who calculated all options before setting on a course of action, at least before he got corrupted. It'll be interesting if this new black dragon will carry on in the same vein. If he turns out to be someone who weighs every option with a keen analytical mind, he could very well play a very important role in dealing with the Titans, when we eventually meet them.

Blizzard's own official preview of the first 5-man is out: Patch 4.3 Dungeons Preview, Part One: End Time - World of Warcraft

It gives a great preview of what to expect, and am I the only one in awe of the brilliantly desolate landscape they've shown in the screenshots depicting the Endtime? It looks awesome, especially Deathwing's corpse impaled on top of Wyrmrest. The shades of the current bosses were an interesting route to take, but the end-boss being Murozond is interesting still. It's an anagram of Nozdormu, so this could very well be the version of Nozdormu that created the Infinite Dragonflight....but what's interesting is that he doesn't look like a member of the Infinite Dragonflight himself.