First off, I love the idea of tanking being viable in a PvP setting. This was most prevalent in SW:ToR, but what they did there is not what I want here: it just wouldn't make sense, IMO. Instead, I'm hoping for character collision to allow tanking to take the brunt of an assault first. Since the ability to step into the line of fire to take the hit has already been confirmed, I think it isn't too far-fetched of a feature. However, I still see a possible buzz-kill to PvP tanks: Character choice. Simply put, I think that the idea of min/max'ing can really hurt players ability to play the way they want to play. In particular:
Will light armor tanks be just as viable as heavy armor when it comes to PvP? Similarly, will we be able to wear any type of armor and still be able to soak just as much damage (if not, will we have an appearance tab option?)... Daedric is pretty much hands down the highest armor value in previous ESO titles: will we be able to wear glass armor just as effectively to mitigate damage? Will Ebony, or Orcish armor be just as viable? I HATE the idea of every tank having to wear the same armor to maximize his ability to do his job. If not, will they give some sort of benefit to a tank to make it a viable option?
In terms of magic, I foresee tanks leaning on Illusion, Alteration, and Restoration. Illusion has fury: I'll be damned if that doesn't turn into a taunt-ish mechanism (I hope it does!)... Alteration and Restoration have more obvious tanking abilities (armor boosts and healing)... Do you think magic will be mandatory, an option, or perhaps tanks will completely forgo magic in favor of solely sword-and-board? Building of that thought, are shields going to be a requirement for the high-end tank?
What are your thoughts/hopes on tanking in TESO?
... all this assuming that tanking is in TESO. Did we even get confirmation on tanking being a thing yet?