Truly there is no simple answer to this.
If you are using a wood fired offset smoker or something like an Ole Hickory Commercial rig then you should wrap, SOMETIMES. The main reason those guys on Pitmasters are wrapping is they are cooking high heat and short hours. Going 275 for eight hours is normal for them, I heard them discussing it on last night's show.
I make a couple hundred pounds of brisket in an Ole Hickory SSG five nights a week. They go 14 hours unwrapped at 220 and are perfect. However if the overnight smoke is not started prior to 4:30 PM, I will have to wrap in the morning. Those briskets & butts would be smoking 11 to 12 hours at 220 until 6:30 AM, then NEED an additional 1.5 to 2 hours wrapped at 270 to be tender.
However if I were making a brisket at the house in my #3, I would never consider wrapping. I would set it for 225 and let it run 14 hours for an average 7-11 pound brisket.
With a water pan in place there is no reason to open that smoker until time has elapsed.
My opinion on Brisket bark is when rubbing them, if you are at the point where you think "It looks good but needs more rub..." Stop applying rub, less is more on brisket, unlike butts and ribs where I prefer "Sandy Beaches"