I think you can kind of already achieve the effect of a flanking using current mechanics. You put a small force in region A, with your large force in region B which is behind region A. Enemy in region C can't scout region B. They attack region A, and your large force moves into region A as well.
Boom. I made a bridge.
It is then up to you to be strategic and figure out if it is a misdirection.
Seriously though, this is never used. Aside from being a bit complicated and relying on player activity, are there any other downfalls to it? It seems like a good trap to me...
