Bark on a brisket means a dried out flat to me. Especially on that thin corner. I'm not a big fan of "bark" on brisket, so can't help you there. Brisket will naturally get a dark smoky outside, but I would not call it bark. Bark is my last requirement when it comes to smoking a perfect brisket. Bark on a butt is a different story. But I like my bark layer on butt not as thick as others. It is a flavoring and textural agent for the rest of the meat, but must not overpower. It's about balance. Too much bark is just plain dry.