Dirk is too old for this squad, but we should definitely go after Parsons (26yo) if he's available. Draftexpress did a FA scouting video of him last year:
http://search.draftexpress.com/profile/Chandler-Parsons-5050/
He could really put this team into contention in the East. He reminds me of PP with his awesome skill level and average athleticism, although he's less of an isolation scorer than a guy who thrives off ball movement. He can make plays himself with his passing+handling ability (career 3.3ast/1.6to per 36), he can knock down a spot-up jumper (.373 3p%), and attack closeouts. At the rim, he makes up for his average athleticism with a best-in-the-league floater. He also plays above-average defense using his size and quickness, and he's on a value contract ($15+m/yr for 2 years).
My guess is that the Mavs will look to keep him, as he's young enough to be a key piece of their core even if they go youth now, but they might want to tear it all down. I'm not sure how the salary would work but if they want to trade him I'm sure we have the assets to get it done, especially since they'll covet getting their own pick back if they're going into tank mode.