(2) Set: Increases the duration of your finishing moves as if you had used an additional combo point, up to a maximum of 6 combo points.
(4) Set: Shadow Blades also reduces the cost of all your abilities by 40%.
And in the recent blue post GC said
- We think we understand the rogue concerns on the PvE 4pc better now. We don't mind Combat having to unlink AR and SB to maximize the bonus, and we still think the set bonus is a DPS increase over not having it. However, it may be the case that the value of the set bonus forces Combat to swap to another spec because the cooldown stacking is one of the mechanics that keeps Combat competitive. To try to (ahem) combat this, we are going to do something unusual and allow the set bonus to also reduce the global cooldown on rogue abilities to 0.7 sec during Shadow Blades. This should help prevent GCD lock / energy capping. Normally we are very reluctant to reduce the GCD lower than 1 sec, so this is very much an experiment.
So, we will see 7 sec kidney shot(with cheap shot it will be 3.5 though) plus 0.7 sec GCD Ambush costing 24 energy during dance+blades, which will allow rogue to spam ambush all the way during the dance.
I heard that rogue burst is already beyond control in PTR, but with the tier bonus it will become worse.