I've always liked Harbaugh I watched him up close and personal at Stanford. The thing is, his 49er coaching days were brilliant, but ended in disaster, there was a much reported "power struggle" with the front office and owners group and with the Bidwills(and Keim) you can see that happening here too.
The reasons to hire Harbaugh? He made Colin K a good NFL QB, his 3 best years were all under Harbaugh and the team fell apart without Harbaugh, as did Colin. CK was a runner who had a great arm, Murray is more a passer who can run IMO but Harbaugh does have lots of experience with a versatile QB like that. He would bring toughness and accountability.
Also it would likely help the defense, remember the guy who ran his defense in SF was Vic Fangio who just got fired by Denver and would be available if he were interested.
I just have this fear that he and Keim and Bidwill would be a very short lived match.