Power users are a mixed blessing.
Pros: they give you many ideas what to do. Often they're your best word-of-mouth evangelists.
Cons: If you take their requests too literally, they can drive the product/service into becoming something with too-narrow appeal and poor learnability. (However, if you don't listen to them, enough, they get mad and maybe you lose their evangelism, or worse it turns into anti-evangelism.)
