The Dallas-area barbecue scene has changed dramatically over the past six years. (Photo ©Michael Ainsworth/Texas BBQ Posse) A few years back, six to be exact, we wrote a “grim indictment” of the lack barbecue choices in Dallas. Pecan Lodge and Lockhart Smokehouse had recently opened, but, we concluded, there was a dearth of joints, especially for a city the size of Big D. Not to mention for the fourth largest metro area in the nation with more than seven million people located in the heart of barbecue country. Why? Were the chains smothering the independents? Tough city regulations? Lack of…