You definitely do less damage, but you can time your burst far more often... since conc blow crits for 4-5k, you can do a dps burst every 30 seconds instead of every 90 seconds (with bladestorm)..
Overall, your damage is 5-10% less, but you are able to control the flow of the game much more... a mage sheeping you across the map? heroic throw silence him.... need to peel for your healer? conc blow the guy and get some mana back...
Losing piercing howl is definitely the worst part about it, but with my druid partner i can call for a roots whenever I really need it...
Spell reflecting for your partner is amazing vs 2 dps, and lol's warlocks pretty hard.... (try it out on mana burn vs priest too!)
Overall the spec is probably harder to play becuase you have less "get out of jail free" cards like bladestorm and piercing howl... but you have access to probably better abilities in aoe spell reflect, conc blow, gag order, and last stand.
Try it out, but dont expect to be amazing with it immediately.. practice in some bgs for a while.
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