You certainly could tank without it -- I and a lot of other warriors tanked up to Naxx-40 with a 31/20/0 build -- but many other warriors would make sure to spec up to Defiance even if they didn't go any further in prot. That 15% additional threat in defensive stance was simply more DPS that each and every member of the raid could put out without pulling aggro. Defiance became effectively mandatory for any tanking warrior in Burning Crusade, especially as rage issues came and went. The addition of expertise to the talent made it even more valuable since in addition to adding threat, it now added a stat that acted as both a threat and mitigation stat. (Removing the tank's chance to be parried reduced his or her chance to be hit with a hasted parry counterattack.)
With the launch of Wrath, however, that bonus threat was simply added directly to defensive stance. (Other tanks had similar talents folded into their tanking styles, as well.) As a result, Defiance was dead ... But as Ghostcrawler (lead systems designer) points out above, warriors got a new talent that effectively became "Defiance 2: The Revenge of the Defiance" with Vigilance.
This isn't to say that Vigilance is a bad talent; it's not, not at all. In many ways, it's a great talent -- well-budgeted, does a lot for one point, makes you glad to spend 31 in protection. But it is both effectively mandatory for any serious or even semi-serious warrior tank and confusing for others to grasp. It's the kind of talent that does so much that it's often hard to explain to people, and those who often want it most are not always the best choices for using it. For instance, I've lost count of the times on tank swap fights that I've had aggro-hungry DPS players beg for the protective shield of Vig -- which would be great except that on a tank swap fight, I want Vigilance on someone I can ensure will be getting hit so that I can ensure that taunt will refresh ... which often makes it a great move to put on another tank. Meanwhile, other tanks hate the very idea of my putting Vigilance on them, afraid that I'm stealing 10 (or 15) percent of their threat. (To be fair, I would be, but on a tank swap fight I'll generally only apply Vig just before I'm going to need to taunt.)
Vigilance therefore serves as a Band-Aid for any warrior threat issues and replaces the annoying Glyph of Taunt (at least, it does if you can convince someone who will be getting hit a lot to let you apply it to him/her). But frankly, having to steal up to 15% of someone else's threat just to be on par with other tanks doesn't really feel terribly awesome. Likewise, having warrior threat be equal to that of other tanks and then suddenly letting warriors choose a talent that gives an extra 15% threat isn't fair to anyone else, either.
Furthermore, Vigilance's taunt refresh is entirely dependent on the target of Vigilance's being hit. What happens if you're using Vig on another tank to ensure taunt transfer? Well, if he or she dodges or parries or is missed, no refreshed taunt. Frankly, the idea of having to use Vigilance or a Glyph of Taunt to ensure taunt transfers on tank swap fights seems pretty bloody annoying anyway. Luckily, the statements coming from Ghostcrawler are making me hopeful.
Ghostcrawler - Re: Taunts missing = interesting gameplay?
I'm going to vote for not interesting gameplay.
At the very least, you should be able to reduce your chance to miss a Taunt to zero if you reduce your chance to miss with a weapon to zero. It's also possible we'll just let them always hit.
So let's review what we like about Vigilance and what we don't like about it.
We like that it gives the target 3% damage reduction. We like that it refreshes taunt, even if we don't like that taunt mechanics effectively force a refresh mechanism or a glyph to reduce taunt miss chance by a ludicrous amount or risk a complete wipe on certain fights (P3 Putricide, Saurfang, Lich King's Soul Reaper). We don't like the threat transfer (warrior threat should neither be so low that Vigilance brings it up to par with other tanks nor given an artificial boost over other tanks via Vigilance), nor do we like that it's basically become a replacement for Defiance, a talent deliberately removed and simply folded into tanking stances/abilities.
Vigilance is a great example of a talent that needs a little refinement in Cataclysm
, one of those infamous "edge cases" that mastery and talent tree redesigns could do something interesting for.
Ghostcrawler - Re: Mastery Design Intent
Every player is going to have a different definition of "boring or bland talents" so that's not going to be a great litmus test. We're probably keeping Improved Overpower. It's the kind of talent that makes Overpower more powerful for an Arms warrior or just makes the ability more powerful in general. Because the talent affects one ability it can have a greater magnitude which is more noticeable than say a 5% damage buff.
Cruelty is the kind of talent we'll replace (probably by making it affect only a handful of abilities) and tanking talents like Anticipation (if we can get away with it).
Making Vigilance more interesting might mean taking away the threat transfer and letting it have some other effect, perhaps allowing a warrior to share abilities like Last Stand or Shield Wall with the Vigilance target. (That would be great for a squishy healer you really want to keep alive; as it is, I often Vigilance the first target of Mark of the Fallen Champion if he doesn't have Blessing of Sanctuary already.) It could make it so that in addition to its taunt refresh, Vigilance reduces the chance for taunt to miss or even allows a warrior to "castle" with the target of the ability, switching places instantly so that a Vig target about to get his face eaten would suddenly be over where the tank just was. (This could be pretty open to abuse and might be too similar to the incoming priest "life grip" ability, though.) Since we're talking about Improved Overpower being interesting/powerful because it affects one ability, it seems likely to me that any future Vigilance changes in Cataclysm
would be safest focusing on Taunt and how to make Taunt stronger and more interesting as well. Taunting a mob gives it a higher chance to miss anyone but the warrior? A silencing Taunt?
Removing the threat Band-Aid of current Vigilance should be helpful in ensuring tank threat balance, which is necessary. Hopefully the coolness of the talent and others on the review table will be retained in the process.
Check out more strategies, tips and leveling guides for warriors in Matthew Rossi's weekly class column, The Care and Feeding of Warriors.