Heart of the Swarm Campaign- Kerrigan Abilities: Ability Efficiency (Level 50)

Ability Efficiency is the most obvious and most likely choice of ability for Kerrigan’s seventh tier, because its effect is most likely to be useful to any given Kerrigan.  By reducing both energy costs and recharge times to 4/5 of their base amount, Ability Efficiency goes a long way towards improving Kerrigan’s activity rate on the battlefield.  All those 50 energy costs become 40s, the ten second cooldowns are shortened to eight and the thirty second cooldowns to twenty-four, and the final tier of abilities get cut by twenty energy and an entire minute of recharge.  Micromanagers will love this for letting them use more Kerrigan abilities more quickly with less concern over the resources spent, and everyone else will still love it for the same reason even if they aren’t as hard on Kerrigan’s energy pool.

This combines particularly well with Leaping Strike and Psionic Shift, which don’t have a cooldown to begin with and thus can be more easily used to dart Kerrigan into and then back out of the middle of enemy lines.  Of the energy-consuming abilities it probably does the least to help Mend, despite the fact that it allows you to heal Kerrigan and nearby units more frequently- the heal over time aspect of Mend doesn’t stack with itself, so you can actually lose efficiency there by healing more often.  Curiously, despite the fact that Zergling Reconstruction has a listed cooldown, it isn’t actually an ability that Kerrigan uses, per se, and therefore doesn’t actually benefit from the cooldown reduction of Ability Efficiency.  Of course, anyone using Chain Reaction and Heroic Fortitude is going to find that this ability is considerably less useful, but frankly those two are the least powerful abilities in their tier to begin with anyway thanks to their more-situational utility and thus this lack of synergy isn’t much of a worry in the end.

As a passive improvement, Ability Efficiency stands head and shoulders over Fury, as increasing the frequency of Kinetic Blast a little bit will produce as much or even more damage and battlefield utility in the end than even a near-doubling of Kerrigan’s attack rate.  Infest Broodlings is a lot harder to rate as better or worse than Ability Efficiency because, while there are situations in which it is going to be more effective than in others, it never winds up being completely useless and in tough pinches will do more to help out- but it still stands below Ability Efficiency in priority in nearly every combat situation that comes to mind.  Having something to tank for Kerrigan isn’t a worry if she has Leaping Strike or Psionic Shift to put her out of reach, Mend or Heroic Fortitude to patch her back up, or Wild Mutation and Crushing Grip to disable and then mutilate whatever she’s facing in combat, to say nothing of the usefulness of Wild Mutation or Mend when Kerrigan is part of a group.