First off, by comparing the blues and greens my tauren is wearing at 80 to the gear my human warrior uses at 70, I can say this: save for the loss you'll see in your crit rate and in how hit rating works as you level (since those abilities require more and more hit and crit rating as you go up in levels) you can easily keep all of your Tier 5 or better gear right up till you hit 80. However, this doesn't mean all specs will get the best benefit from current itemization: arms and fury can wear DPS gear currently in game with little penalty, but protection spec will find themselves not only severely overgeared for the first instances they walk into, the new AP scaling and strength to block mechanics mean that their gear is no longer optimally itemized for threat.
Also, devastate is currently broken. So that makes it hard to judge how much threat prot really has vs. how much it needs, but even with that it seems that if you are wearing tanking gear from current endgame, you're going to need to throw some DPS pieces on. I tanked UK, the Nexus and Drak'Tharon in PvP gear with tanking rings and trinkets and it seemed to help immensely with rage gen and threat, and as you level up you'll see gear itemized to the new scheme of things. I found prot to be greatly improved for soloing and grinding as long as you geared for the new realities, but it's true that trying too hard to hold onto the old itemization can hurt you here. Prot is still scheduled for more work, so I wouldn't worry about it too much (and I have another warrior I'm going to level once the next beta patch comes out so I'll be able to report on the changes) but for right now, you can level in any spec you want. Fury is the fastest to kill with, prot the easiest to stay up with (level 73, I barely took any damage at all leveling prot in Kara/ZA gear) and arms has elements of both and is greatly improved since the last beta push. Bladestorm still kind of sucks, though. I'm sorry, it does: doesn't last long enough, doesn't do enough damage to compensate for the damage you can't do while you use it (no white hits, no other specials). But Wrecking Crew is very nice, Unrelenting Assault is pretty hot, especially if you have Taste for Blood, and Trauma has nice synergy with the rest of the tree. I ended up staying in Battle Stance for a while on my arms warrior so that I didn't have to keep switching back to use Overpower, because it felt like the ability was always up and always ready to go.
In my estimation, we're 75% of the way to all three trees being viable for soloing, grinding, questing and PvP. Yes, even prot. Either arms or fury can tank in a five man capacity, although prot is still clearly superior in the proper gear (bugged devastate nonwithstanding). Warriors aren't perfect yet, nor do I expect them ever to be, but overall there's a definite feeling of progress.
I don't know why, but I was asked to DPS in instances as much as I was asked to tank them, if not more. As this writing I've been DPS in the Halls of Stone and Caverns of Time Stratholme (I got a really ugly hat with good stats in Halls of Stone, which made me wish I'd taken the tanking hat from the Sholozar questline) - DPS as a fury warrior is fairly simple: hit things, raise everyone's crit rate by 5%, hope to reset your cooldown on Bloodthirst or Whirlwind, watch for Bloodsurge and use as many instant slams as you can. Sometimes throw Demoralizing Shout up for the tank if it's a DK or paladin. Arms DPS is much, much more based around the bleed effect and getting self-enraged through the Wrecking Crew talent, then burning off your enraged state with Enraged Assault. I got lucky enough to run Drak'Tharon as arms with a fury warrior, feral druid tank and enhancement shaman and the raw melee synergy was gorgeous to experience (the rogue probably liked it too). Either way, melee DPS as a warrior is more engaging now, with more to do and procs to watch for and choices to make that simply weren't there before.
Tanking as arms or fury is basic: sunder, heroic strike, your big instant when you have the rage, keep using whatever abilities you have to try and hold group threat. My fury spec uses Incite as a matter of course, but I forgot it when I went arms, so my fury spec tanked better. (You could make an arms spec with it fairly easily, so that was purely my screw up.) And yes, I tanked in fury with a 2h and shield. It's not the best way to go, but my 2h sword has such ridiculous crit and attack power that it works.
Tanking as prot requires that you adjust your gear for more strength/AP for scaling abilities, but it's actually a lot of fun once you adjust for the bugs. Sword and Board could be better (some outright think it useless, but it seemed to be up a lot for me) - I still have a hard time with the new Shield Block, even when I talented it down to 40 seconds it just seems an eternity for an ability I'm used to spamming, and I get a lot less use out of Revenge as a result. When you're geared for it, Shockwave and Thunder Clap can put out some reasonable DPS and threat, but I'm starting to think that the stun of Shockwave hurts in instances: for an ability that I can use every 20 seconds, I sometimes hold off on using it because I want to make sure everything is hitting me enough for me to get some rage before some real AoE gets dropped. Stunned mobs don't anger me, apparently. I would like it if Incite also worked on Shockwave, frankly, I'd use it more and not worry as much about the stun. (My current workaround is to use Shockwave and then Thunder Clap almost immediately after it, assuming the mobs are in rage, and if I have the rage left start throwing cleaves around in tight group threat situations).
For damage reduction, I'm really liking Critical Block. And the new Shield Wall is the best of the formerly linked cooldown abilities, especially improved with talents. (I'm afraid Reck is as useless as the detractors said, I admit my eagerness on this one was misplaced. Three yellow crits is nothing. This makes me very sad.) Shield Wall is now viable for at least two uses in any boss fight, and can be used in AoE tanking once you're pretty solid on threat: the 60% reduction is less then the old 75%, but having it every four minutes means you'll use it a lot, and take less damage overall. Combined with the way Shield Block works now and with Last Stand, it starts being very easy to reduce spike damage as a warrior or reduce the threat that it will kill you.
I have not noticed if the concerns on the beta forums about recent threat gen are valid or not. One would assume that if they are it will be fixed by the time that patch 3.0 goes live and we have new talents to play with. At least I hope so, as my main is prot and probably will be remaining so for his guild. As long as Devastate is fixed and the threat issues are smoothed out, tanking in general should be fine.
What amused me was that I did nice DPS as prot in a Halls of Stone run! Now, I didn't blow anyone's doors off, but in full DPS gear, my crit is good enough that I could use Shockwave as an offensive ability, and since Incite gives my HS, cleaves and TC a solid 15% more crit, and I could spam Devastate (which is still an instant) I found myself approaching low fury levels of DPS. Now, some people have always argued for prot DPS in such gear, so those people won't be surprised, but changes to abiliies like Concussion Blow and Improved Shield Bash actually made DPSing with a shield as a kind of 'offensive offtank" viable once or twice.
I haven't raided yet (in fact, I'm not even sure that they've implemented any raids) so that's as far as I can really discuss things. I've PvP'ed in Wintergrasp and need to do more of it to get the PvP blues, but spec is less important there than the fact that I have no resil on my current gear: I get owned a lot, but I can do good damage with Arms or Fury when I'm not being burned to death in my totally unsuitable gear.
That's enough of me. Level 80 doesn't, to my eyes, seem overpowered or underpowered. Fury doesn't dominate for DPS or PvP, it's different but viable. Arms can still do DPS or PvP, it's simply less focused on direct damage and more on crits and procs and bleeds. Prot is still the king of tanking, minus some bugs, and can even PvP or DPS if necessary on a much more even level, although clearly it's never going to be mistaken for Fury. There's a good deal of parity between the trees while they retain their uniqueness: you'll never mistake a prot warrior in DPS gear for a fury warrior.
And yes, Titan's Grip and I are still very happy.
Next week, who knows? It depends on if Blizzard gives me a second to stop and think, really.