Your suggestion indeed will be easiest to implement, but then expect there are some 50-100 anger-venting posts every season.
However, just think about those several 9th-position teams in level 32 who was expecting to stay in the same division and did their best preparations and bought several 90%+ players by end of previous season with some 30T or more to prepare for their next one, and then suddenly got promoted to level 33 against their game knowledge and will, and the promotion has left his bought players useless (would have bought in the new season if he/she was told clearly they would get promoted).
And it’s even worse to not promote those level 33 teams to level 34 if the league rules state clearly top 8 teams are promoted when they would have decided to keep some of the players instead of selling them if they knew they would be staying in the same division.
Of course the admins can excuse all of the above with the ‘exceptions’ that the game has the final rule about fair play or what not. But it is more than likely those players who suffered from the above will be rightly aggrieved and decide they may not invest in the game anymore or even quit when emotions were running high when they feel the injustice of ‘why only me?’ among some tens of thousands managers or more.