The crazy thing is, Snyder may be able to get the gang back together if he really wanted to
It would be smart to get Mangino back, but they hate each other, so that's out. Obviously the Stoops boys and Venzy aren't coming. He's got Dimel, and Leavitt is there to be had (presumably)....but I don't really see any others (of any worth) he could get. 
Mangino will most likely have a decent gig going into next year. Some school in C-USA or something will give him a chance. Miami was the first big domino to fall, so there will be at least two or three openings coming from that alone. Same with Minnesota.
I could see Leavitt coming back if nothing more than to rebuild his image. He doesn't have to be HCIW to come here. Every year he sits in Tampa and does nothing, it's one more year that the last thing on his resume displays, "Fired for allegedly hitting a kid."
I'd love nothing more than to see Mo step down, Joe Bob to go (which won't happen, but I digress), and then watch us bring in Wesley McGriff from Miami (maybe this time he'd stay for more than a few months?), bring in Leavitt, and then go get Chris Wilson from Mississippi State to Co-DC with Leavitt.
THAT would be an upgrade from a recruiting and coaching standpoint. I'd keep Burns. What he's done with the patchwork CBs and Zimmerman have been great.