How so? Simply balancing the levels without remixing the channels so that portions of the signal for one channel are steered to another would not have the same effect.

Something like Logic 7 that had very good steering built into its processing, yes, but simple level and delay would not do this. You don't want each speaker to be equal to correct for bad positioning, you want each signal to be equal, and it may come out of two different speakers instead of the one it was destined for to do that.