As Smokin' was pointin' out, a small piece of meat that needs cooked for an extended period of time has the tendency to dry out if precautions are not taken to help.
Choice product means there is a chance that the meat has internal marbling that will help with moisture and taste...but you would have been much better off with a packer brisket that has a layer of fat to help moisturize the cook.
I'm with Smokin', wrap early in foil(150-165*) with some type of juice/broth. It may produce a pot roasted type of finished product, but will be better then just crock pot brisket.