I doubt that this is as easy as it sounds. It would have to know about your other gear, your talents, and what attacks you intend to use. I'd love something like that, too, but I kinda doubt that it is doable for anything more complicated than, say, spamming frostbolts.Quote from
I suggest the author to ad calculation about how DPS changes with different gear.
There is specialized addons like TankPoints, CatPoints, Enhancer and lots more that can do this job.