You are allowed to be in debt in football be it in games or in real life. You are also allowed loans. As long as you fix the debts or pay the loans in time, there should be no problem.
I understand what is your concern as last year (2015) I faced a user who was one level higher. He bought several 5 star players (which were 6 star players for my team level) at the start of the season and went in debt. His team knocked my team out of the cup early in the season, probably because he had a better squad for that period, and later he lost some of his players, and was knocked out of the cup in the later stages. Of course, I was annoyed because my team could have progressed farther had he not bought all those 6 star players.
But, this is part of the game. You can do it too if you want. There is nothing wrong in that. In fact, it can be used as a strategy.
So, I don't agree to your suggestions. This part of the system is already good enough and simple as it is, and going by your suggestions will make it more complicated.