The problem is how many top players are going to sit it out? We've seen how good the turnout can be for IR - pretty bloody abysmal most years.
I agree that all other things being equal, post season is the best time to hold it. But all other things aren't equal, and I reckon 50% of the players selected won't play. Pre-season I think you'd get 80%+ putting their hand up.
I agree with you pre season is the go and I think it should be shared around with matches in Adelaide and Perth which I reckon would sell out with the proceeds after costs going to a local charity..