The Heat would do it in a hearbeat. Marion is a free agent next year, while Hinrich is younger and under contract until 2012. Plus, the Heat need a point guard (Mario Chalmers is a nice backup, but that's about it) and are well stocked at the pf position with cheaper players like Beasley and Udonis Haslem.
No brainer for Miami. The question is what Chi is willing to throw in to make the salaries match.