Really? I think Gallen just inspires with his actions. I don't think he says "okay boys we're 12 in front and they're looking tired, let's keep the ball in the field of play and play field position and tire them out. Then in a set or two we should be in good attacking position and get a try or repeat set". Or "Okay guys, we are 20 behind and it's the second half, what we're doing isn't working. The Raiders have good attack and have put some points on us but they also have horrible defence. We can get back into this if we threaten them a bit more. Whatever you do, do NOT kick the ball over the sideline for a scrum. We are chasing points and need to start doing that"
We need a half that can think about strategy and help the team implement it. Someone to be the brain of the team.
That to me is an organising half.
Then other good attributes are to know when wingers have dropped back, know which defenders are having an off game and send the traffic their way, get the set plays going, change things up a bit, kick hard and chase hard etc.
You don't need to be physically a great player to achieve this, just a smart player and a cool headed player.
It's why Tim Smith was SO bad at it. His head was just not capable of this.