Agree on the TPC. While I can't say I'm a fan of the course, putting it there would be the M.O. of the Tour.
Baffling to me that Radrick Farms would be on the list. Staging any event there with a crowd seems completely illogical. A few holes have barely enough room for the players, not to mention a gallery (#13 and #18 come to mind). It tips out at 6,967 today, with a par of 72.
Sharf gets to 7,100. Haven't played it in a while, but I think there would be ample room for gallery flow. However, I'm not so sure Gilbert would embrace a course up in Oakland County, or any of the suburbs for that matter.
DGC is the only notable place that checks the box of being in the city. In some ways, putting a tournament at DGC could be similar to the commitment made to East Lake as far as improving the surrounding area.