The case for Kidd: I didn't realize Kidd had played a total of 8 years with the Mavs. A quick scan of the numbers shows him at about 10-9-5 with 1.8 steals and a solid A/T ratio for the Mavs. Started at PG for their title team.
The case against: Kidd only played for Dallas at the beginning and almost-end of his career; he spent his prime elsewhere. Left for another team after winning a title in Dallas. Never the franchise guy for Dallas, never a number one option, a defensive liability in the title run. While he racked up assists, the offense didn't run through him.
To me, there are two reasons for a team to retire a jersey: either a transcendent player who carried and became the face of a franchise even if it was only for 3-4 years, or a good player who dedicated his career to the franchise. Overall Kidd was a good player for the Mavs, with a career worthy of the Hall of Fame and the kind of guy who is a no-brainer if he had spent his whole career in Dallas. On the other hand, if you ask people to picture Jason Kidd they see him in a Nets jersey. That kind of clinches it for me. He's not REALLY a Dallas guy, which he showed by bailing for New York.