Also, if the Warden were 20 pts then its actual cost would be 25 pts, since you're paying 5 pts for the hook. So we'd have a the same armour, turns, hits and turrets for the same cost. The Warden would have +2WBe maximum firepower. However, to use that the Warden does have to go prow on and it is heavily restricted in the fleet in terms of maximum and practically speaking also in terms of minimums, since points are already invested in the hooks. And the Iconoclast is faster.