Are spellcast interrupt abilities, such as Kick, too good? It’s easy to make that argument. We think their ease of use and low cooldown has led to a whole cascade of events in PvP. Because interrupts are so good, casters without a lot of instant spells or mobility are weak. For that reason, we tend to give casters a lot of instant spells or movement abilities, and casters who excel at those (say, Frost mages) are very powerful, while those without (say, Elemental shaman) have more difficulty.
Because interrupts are good, classes without them feel uncompetitive, which has led to us giving interrupts to paladins and druids, which in turn has led to them being even more prevalent. Because casters tend to fire off lots of instant spells while jumping around, melee can be really easy to kite. Because melee can be easy to kite, melee classes without strong mobility can suffer, and we have to consider giving high mobility to all melee, which increases the amount of uptime melee have on casters, which means we have to give casters even more powerful escape mechanisms to survive... and the arms race continues.
See where I’m going with this? Because instant spells tend to be so powerful, we have to make cast time spells insanely powerful to compete or they’ll never see use in PvP. But we have to make those spells so powerful that when they do get off, we can have PvP burst issues. (Look at how much better Frostbolt has to be than Ice Lance for mages to even consider the “long” cast.)
Nerfing all of the interrupts across the board isn’t the kind of thing we can realistically do mid-expansion. Anyone working on the raid content can tell you how important interrupts are to today's encounter design. We’d have to redesign nearly all of the raid encounters and many of the dungeon encounters as well. Of course once you increase the cooldown on interrupts, then availability of stuns gains relative power, so you have that balance consideration as well.
Instant spells do have their place in the game. If you’re worried about being interrupted because someone is chasing you, or you are chasing them, that’s a great time to use an instant spell. But actual 2.5 sec cast time spells need to have their place too and, if anything, they should be the norm.
Here's one other way in which interrupts have wide-reaching effects on the game via the chain of consequences discussed above. One of the advantages melee used to have in PvE was on movement fights. If the boss has to be kited or stays in motion, the rogues and warriors can follow along and still deal damage. It will be less damage for sure, but they’ll still get a lot of auto attacks in. It used to be the case that asking the Balance druid or Fire mage to move was a huge dps loss for them, because they were always interrupting their spells. In today’s PvE environment, that role has almost flipped. Many casters can shoot on the run and take only a very minimal DPS hit to do so. For this reason (and a few others) melee classes can feel like a liability on certain encounters. We’d prefer for raids to want a fairly even distribution of ranged to melee classes and ideally groups would have a lot of flexibility in who they bring. It’s okay to have fights that are really good for casters, but there need to be at least a couple that feel great for melee as well.
Is there a design lesson to learn here? I guess it’s some variant of the butterfly effect -- apparently innocuous designs (in this case the short cooldown on interrupt abilities) can have wide-ranging effects on all aspects of the game. I’m not sure what the game would look like if Pummel and Kick and Wind Shear had 30 second cooldowns. Clearly we’d have to redesign a lot of other abilities, mechanics, and numbers to make it work. Again, this isn’t a change you’ll see anytime soon. But it might feel better in the long run if we could get to that point.
Greg “Ghostcrawler” Street is the lead systems designer on World of Warcraft. He knows how to get to R’lyeh.
