Vanish isn't a problem...

We're not happy with the current Vanish fix on the PTR.

Even at 0.5 seconds, the rogue sometimes gets hit by a missile already in flight. Yet, even at 0.5 sec it's too easy to screw up using AOE to break the stealth, which is a totally legit counter in our minds. Therefore, making the immunity longer or shorter causes other problems. As I said earlier, the attempt was *not* to make Vanish into Cloak of Shadows Jr. We're not trying to offer a big PvP buff to rogues. We just want the ability to work as advertised. The intent of the 1 sec (then 0.5 sec) immunity was to provide a little padding so that the ability didn't fail in situations where it is supposed to succeed. I'm not sure it's doing that though, and it's causing other problems.

The way we want it to work: If you Vanish after a single targeted spell is cast, you're safe, even if the missile is still in the air. If an AE spell is cast on you, even if you just went into stealth, it should break you out.

We're working on a hopefully better fix now where we record the time that a missile leaves the caster and compare that to when the Vanish is activated. There still might be edge cases though that this doesn't fix, if for example the cast and the Vanish happen very close together and someone's client isn't updated quickly enough. TLDR: It's complicated.

For perspective, in patch 2.4 prior to LK, Vanish was more reliable in the situation I'm talking about above: used after a spell was cast would make you immune to the spell. It had some other bugs at the time, but all of those that we know about have been fixed. We have made many changes to the way spells work in the 3.X cycle, and one of them made the situation bad again. We need to get the conflict between missile travel time and Vanish resolved the way it used to work. The bad news is that since this is a code fix, it might not make it into 3.3. The good news is that because it is likely a server fix, it doesn't need to wait for a major patch.

I'm also going to stamp this with "no promises" since unreasonable players may start complaining if Vanish isn't fixed in exactly one week from now. :(

P.S. I used the word "spells" a lot above because to a developer, everything you do in WoW, even a melee attack, is a "spell." It isn't necessarily confined to what players think of as spells, such as Fireball.