Was thinking about this after watching the 2011 win over the Storm to put us in the GF. Letting go Cleary is easily our biggest. That decision, and the many following sent us in a downward spiral which we are still in. Cleary isn't the greatest coach, with his forwards in the centres, bomb to Manu plays etc. But he brought stability, decent defense, and the players loved him and played for him. He developed our last decent Warrior forwards. Things we haven't seen since. Maloney may have stuck around. Nathan Cleary could/would have been a Warrior. Imagine a Johnson/Cleary halves pairing!
Instead we went Bluey (rose tinted glasses signing, no substance), Elliott (what the f**k were they thinking, a known failure), Cappy (not terrible looking back, just not quite up to it) and now our bumbling mate SK.