Mornin'
My preferred playstyle is tanking, although I dabble in healing some times (I svck tho )
Anyhow from what I think I know about the game so far we will have the trinity and therefore tanks.
I'm wondering on how that will work out...
The MMOs I know so far will require you to specialize completely by spending most of your talents
on passive tanking requirements, i.e immunity to critical hits, taunts, high health/armor etc.
Now TESO will give you a bunch of skills to choose from and I guess one would use tank appropriate
skills such as emergency buttons, taunts and high aggro abilities.
What I wonder about is passive specialization as a tank...any word or known facts on a perk system?
Comparable with skyrims system for example in which I can bolster my heavy armor? Or would wearing
heavy armor impair dps/heal ability, discouraging anyone but tanks (in PvE) from wearing it? Could
tanking/avoidance be a more active process in which one needs to use skills to soak blows (not only
active blocking but say the ability to dodge the next attack after blocking the preceding). Now that I've
typed that, it sounds like a lot of fun actually. Instead of just standing there and getting smashed in the
face with additional tasks thrown in like *kite boss from left too right and back* actually avoiding
blows. Whats your take on this?

I think you've really got the wrong perspective on what being a "tank" in ESO will be like. You're describing a lot of WoW tank aspects. Although there will be aggro it will be very loose. Its not like there will be abilities to generate aggro at all. As far as being a "tank" you can beef up your health, heavy armor, use a shield, and choose defensive abilities, but not taunting or aggro gains. No passive avoid/parry chance. Chance is frowned upon in this game, hence the real time blocking. As far as passives, you get "tank-like" passives for putting points into health. Regardless of if you want to be a tank, if you're putting points into health, you're trying to stay alive right? Haha. So things like extra healing done or health regen. So from what we know I would say that there are plenty of ways to make your character beefy. Take my position for example. I want that warrior who runs in the middle with a two handed sword, but is a nightmare to take down. Nice solid dps, but with all my heavy armor bonus, health perks, and maybe a mix of defensive and offensive abilities from say the Dragon Knight class. (Ret Pally from WoW, if you're familiar. Less heals and more armor rating) I think that sort of thing is possible. You can also go full defense with a sword and board build if thats you're thing of course. I just don't think the classic aggro control tank will appear in this game. Doesn't mean you can't be a defensive powerhouse leading the pack and holding down the front lines.

Edit: I didn't really address the whole heavy armor taking away from dps/healing importunity. I'm really curious about that myself. Like I said I want to dish out some serious dps, but still be tanky. I would imagine that there would HAVE to be something to lure say a sorcerer to cloth armor. Like in past TES games, maybe having magic regen or mana boosts on cloth wear. You want to be a tanky healer? Well you can do that, but you have to sacrifice the mana bonuses found in cloth for the extra defense provided by heavy armor. Something along those lines I'd think.

Not to veer to much from the original post but I doubt something like *loose aggro* is possible.
You can have mobs attack randomly. You *could* have them attack the biggest threat i.e. the
healer or a particularly squishy dps. But AI isn't far enough for that yet. Or you do as any game
that uses an aggro table works, assign threat numbers to distinct actions. To *loosen* the aggro
table you can have the values rather similar, making it hard for the tank to hold aggro and mobs
prone to run at the healer as soon as he finishes his spell or you can throw in low danger mobs
with random aggro or you could use other tricks such as the mobs switching between spot 1 and 2
in its aggro list. But however you look at it, in a system that uses aggro and tanks, you will always
have abilities that are better to generate aggro and those will be tank abilities.

• Enemies are designed individually pose a challenge, and be more than “speedbumps” in the player’s quest. Groups of foes will work collectively to support each other and use control abilities to counter a player party. The behaviors of enemies in PvE are designed to mirror player classes. The same abilities and mechanics are therefore important for both PvE and PvP. It is an important design goal that combat versus monsters has the same feel as combat versus players. Monster AI is also designed to emulate player behavior; ranged attackers will fan out, sturdy meleers will protect fragile casters, and healers will seek cover behind other mobs.
  
• “Aggro” tables of NPC enemies are less rigidly defined, and they may systematically switch targets in combat. This further emphasizes the need for players to assert personal responsibility for defending themselves in combat, rather than relying on traditional aggro management.

source: http://tamrielfoundry.com/development-faq/

Well i just meant as far as aggro abilities or being "the guy who takes all the damage" I really don't think they're going for that gameplay where you either heal everyone like a maniac, tab-target a mob and press your rotation relentlessly, or aggro all the mobs to attack you. A point to bring up that may give you a better perspective is that they're trying to simulate PvP within their PvE system as much as possible. You don't see everyone in a battle ground swarming the tankiest guy like mindless drones do you? No, they play tactically. Of course aggro is in the game, but I really don't it'll be like what you're used to.

If PVE is going to be like PVP then let's see....tanks are hard to kill but are usually pesky annoyances. It takes a lot of effort to put down a highly defensive character. Usually it's best to just crowd control them. I predict the OP will be CC'd often.

Agro will work a bit different in ESO it is more LOS then it is just how close you get to something, there will be no pulling one group of mobs at a time because as soon as you tap one mob in a room they will all know you are there and they will begin their strategies against you and or your group.

For more detailed information on this I suggest watching this interview: http://www.youtube.com/watch?v=ayT_9USmIbg from about the 9:00 mark on Maria talks a bit about agro in ESO

It will also be interessting how stealth will work ingame.

I can already see it: "Tank is losing aggro! Everybody, Plié and crouching" ^^

I saw it often, Warhammer BG it was painfull to see.

@OP I don't think that you can tank the same way you want too, but there is a skill you can use. A chain that pulls the traget to you and than baound it to you for a short duration.

We dont really know a whole lot, except they are trying to break the tank mold used in so many previous mmo's.

Tanking will be much more dynamic in this game. Even though there will be chatracters that are more defensive (I plan to be one of those) everyone will be responsible for staying alive. I don't think anyone will be able to forget everything because the tank and healer are taking care of it and simply sit there and DPS, it will be on everyone to reduce the amount of damage the enemies cause by using CC, interrupts, cleaver use of dodge and block. So actual "I am the tank and all mobs hit on me only" kind of tanking won't likely be seen in this game.