as I said... all options have some faults :)
And still the current problem happens with less than 5% of the teams in the world of BB. If some changes are made - they will be for everyone. The idea is not to make more harm. I mean that it could become even worse. Also don't forget that all these changes will influence on the global BBeconomics.
So it is not a 5 minute decision.
Example:
1. Changing the selling % would lead to global change of economics. If not adjusted correctly - it could lead to inflation/deflation again. Noone is happy with that.
2. The team not able to use the player during xx weeks. Baaaad. Imagine if your players get injured. Also it would harm to new users. Hey, you've just bought a player, but wait 2 weeks to play. No.
3. Salaries need to be paid for at least the month(4 weeks). It is a good decision. Since really noone in real life can get a contract for less than a month :D I don't see huge disadvanatges of it. Though still it needs to be estimated better. And it should be also easy for the users to understand and see that.
Sure this suggestion won't stop buying begemotes to win the single game, but it will damage the team harshly..