I personally believe (from I heard), Redman is staying for less money at Essendon than what he would have gotten at Adelaide.
The sticky point was the length of the contract imo. No harm in the Crows keeping the Bombers honest and probably forcing them pay an extra 100 K P/A than what he actually is worth though.
It usually costs a premium to make a player move (your Blues would know about this).
Which feeds that BF narrative of "all our blokes took unders to stay because they love the club and everyone who left is a mercenary flog"