I definitely don't think the Mavs are trying to tank. First, and foremost, they have Dirk who is nearing the end of his career - the last thing he wants to do is tank. Next, they made big signings (and re-signings in Matthews, Williams, and Barea) and traded for Pachulia. I know Matthews is supposed to be on a minutes restriction, but he apparently looked pretty good the other night and that restriction may end sooner rather than later.
And finally, DeAndre Jordan just basically ripped them off and they were left with a middling team. I think we can expect a pick in the 12-14 range (where we hope the Wolves pick also ends up :0)