We have one 3/4 and it is Marvin and our only true backup center is biyombo. MKG is a 3, cody and Vonleh are 4s.
We need veterans to help bring the young guys along. Marion has been on winning teams for awhile now. It'll depend on whether he wants to be a mentor at this point in his career or try again for a second ring. I'd take his experience here in a heartbeat.
I dont see Marion as enough of an improvement to warrant taking away minutes from our core. I'd rather see Cody, Vonleh, and Biz get the backup big minutes. I think a healthy Taylor and Hendo are more than capable as backups at SF. Add that Lance can slide down in small lineups.
MKG and Marvin are 3/4 tweeners.