I must admit I was wrong about opportunity of opponents to ignore decoys. I experiment a bit with my orges and humans teams in Dueling Grounds, hammer vs sword. And there is no possibility for clever code against decoys as @Deadpool198 mentioned (or I didn’t find it) ). In jasoneilif case looks like distance to decoys>30 and smth like target=friend.findNearest(enemy) makes his allies attack me in spite of decoy on arena.
But without decoys non-subscribers have no chance on the Dueling Grounds I would say. And even with decoys it’s very hard to compete with subscribers, and almost unreal if the subscriber have good coding skills.
It seems to me that goliath is a wrong choice for Dueling Grounds. Necromancers, assassins, sorcerers, potion-masters, librarians and trappers are more powerful themselves and/or with allies prop-up.