Well, to everyone's surprise - even those like me who were expecting Masksmanship Mastery to change - we MM Hunters are now planned to have Sniper Training as our new Mastery. For those who are not following the news:
Sniper Training: If you don't move for 3s, you gain a buff that provides 4% (improved by Mastery) increase to damage, range and critical strike damage of your attacks. This buffs endures while you stand still and for 6s once you move.
At first glance, this new ability is amazing: it fits thematically, it's quite powerful and is a lot more interesting and fun than the old "Wild Quiver" Mastery.
With the new combat model focusing less on movement during fights, MM Hunters would have no trouble maintaing this buff over the entirety (or at least majority) of a fight.
But this new ability has a terrible flaw. While perfect for raiding, most group PvE content or while pet-tanking, it's terrible for anything else, specially PvP. In a PvP fight, or if you decide to go Lone Wolf, or if you are in a situation where your pet can't hold aggro, it may be impossible to stand still. It also has terrible synergy with Hunters defenses. You moved away from melee? Disengaged? Well, I hope you now have 3s to stop and breath, or you lose it.
Having a situational ability like that would be fine if it were a spec passive. If it gave a flat 5% bonus, I would not be complaining: it would be great for when you can use it, and useless otherwise. The real problem is that it's linked to Mastery, and Mastery provides no benefit whatsoever if you are not under the Sniper Training bonus.
Consider this imaginary setup. You have gear that provide you with 75 Crit, 75 Haste and 75 Mastery. Under Sniper Training bonus, your gear has full effectiveness. But once you lose the bonus, you effectivelly has 75 Crit, 75 Haste and no Mastery. In practice, you just got your ilvl downgraded.
Now put that in situations like PvP. Every single piece of gear that has Mastery automatically becomes a terrible choice. "Just avoide Mastery gear"? It's not that simple. It's one thing when a stat has less value for a spec; it's another when a stat has the potential to have zero value.
Compare current MM (MoP). Mastery is our least useful stat, but even if we avoid it like the plague, it still adds value to our gear. It is still useful. Having 50 Mastery is still better than having 30 Mastery, because there's a increasing benefit, even if it's a small benefit. Sniper Training would be different: once you lose the bonus, having 25 Mastery is the same as having 1500 Mastery, because you essentially gains nothing out of it.
Now think about this: no Reforge anymore, and PvP Gear has a lot less variety than PvE gear. Can we avoid having any Mastery at all? And what about all those times we get a new piece of gear that should be better than our current gear, but it has Mastery, and thus its value is reduced?
But how to fix it? My point is that Blizzard should do one of the following options:
Solution 1: Untie Sniper Training from Mastery
Basically, Sniper Training becomes a MM Passive with a flat bonus and we get a different Mastery. Sniper Training will still be useful in PvE and almost useless in PvP/Soloing as Lone Wolf, but at least it won't downgrade our effective ilvl.
Solution 2: Add an always active partial benefit to Sniper Training
Example: Sniper Training provides a constant 2% (increased by Mastery) bonus to damage, range and crit damage. When you stand still for 3s, that bonus is doubled, essentially working as the current design of Sniper Training.
That way, Mastery still has value at all times, even if that value is diminished. Having 75 Mastery will be better than having 25 Mastery, even when moving, instead of becoming worthless.
IMO, this is the best solution: in raiding, you'll still need skill to do full DPS. In other situations, Mastery still has some value attached to it at all times.
Solution 3: Add an Alternate benefit for when the Hunter moves
This is like the previous solution, but instead of a partial benefit, MM Mastery also adds something that is active regardless of the Sniper Training bonus.
This could be a defensive benefit for PvP, like "Increases Movement Speed and chance to Dodge attacks". It could be something else. The point is for Mastery to still provide us with something when we are forced to move.
What are your thoughts?
TLDR: Sniper Training is a very cool ability, but it must not invalidate all Mastery stat in your gear when you are forced to move. In its current iteration, Sniper Training is a flawed idea that's awesome for PvE group content, but incredibly gimped for anything else.