Based on a lot of testing, I've determined that it is not obvious how it picks its targets within 20 yds. While testing it on the dummies, I provided people outside of my group with the buff. And even more importantly, while in a raid group, the staff appeared to provide the buff to everything from players to guardians (Mirror images and Ebon imps included).
Wow, I never would have imagined that it would extend the buff to pets/people not in the raid group. Seems kind of uncontrollable from what you are telling me. So here's the questiong that's been racking my brain for the past day or so. Which is going to be better, the Legendary staff or Ti'tahk, the steps of time? Considering that some warlocks are hitting the soft haste cap while in raids already (30%), what good does the proc off of the 416 staff do for you? I realize that it may be more of a raid buff than a proc for those warlocks that are at the soft cap, but other than that, aside from the added stam, the 416 only has 5 more intellect (with current gems) than the Legendary. I might add that when 4.3 hits, this also means that we will be seeing epic gems, which will most likely make the Legendary staff have more Intellect than this 416 staff. On top of all of this, if you are one of those warlocks at the soft cap, the Legendary proc seems to be more of a dps increase than anything (keeping in mind that they nerfed the proc rate). Curious as to the testing and/or some others' thoughts on this. Oh and before I get nailed on this, yes the 416 staff has 539 more Spell power, but will this overcome the proc/ intellect with epic gems on the Legendary?