Nets’ trip to Dallas offers reminder of what could have been — and what lays ahead

DALLAS — The Nets’ game Friday in Dallas could’ve been a reunion with Kyrie Irving, and a stark reminder of their ill-fated Big 3.  Instead, it’s a cautionary tale about star hunting, and reinforcement for Brooklyn’s new holistic approach in the apron era: Tank. Draft. Develop.  “Well, I have to say that we’re in a…