Jskd82, unless you have access to a 360 range, how do you propose to have shooters engage targets to their rear, unless in the context of something akin to El Presidente?
You suggest it like it's the simplest thing, but most ranges are simply not set up to accommodate that kind of a drill.
The indoor range used by my IDPA club has three bays, with steel reinforced walls. We are still not able to do a 360 shoot-house, but we are able to set up simulated corridors and side doors, and engage targets to either side. Even so, for safety of the Safety Officer / Observer and the other shooters behind us, we can only turn about 80 degrees to either side of straight down-range.
Your derision, and your suggestions which imply that training to engage targets to the rear should be so easy as to be commonplace, make me doubt you've had much training or range experience.
(Note that the only 360 training I've had access to was at Fort Jackson, using M-16's with Blank Firing Adapters. It's hard to find 360 live ammo training.)