From my point of view FFP has lots of different consequences
- Clubs can't speculate with leverage/loans way past their means, lowering risk of going bust
- Huge money investors have to spread out their investment over a longer time period, stopping them from being able to compete as fast
- Already established clubs protect themselves somewhat by limiting new clubs spending big to catch up
- Without FFP super money investors can inflate the cost of wages and transfers, even with the limitations you can see the rise taking place, partially driven by City and PSG
- Forgetting about the already established clubs protecting themselves, well run clubs who maintain themselves well lose out by being pushed down by the big money investors. Clubs like Tottenham, Everton who work for years on their squad, lose out on Champions league that they may have reached many times if City/Chelsea never got their big money boosts. Is it fair to those teams running well (though I hesitate to say that about Tottenham more recently) that their developement never got them the rewards they strived for. Same applies to multiple French clubs who may have won league titles over the last decade otherwise.
I think there is good and bad to all this. From my perspective I think clubs should have some limitations, as I don't want unlimited money coming in. I think it needs to fix two specific things in different ways.
Firstly unsafe investment, so the current setup is pretty much in line for this. I do think better structure to stop usage of loopholes and fraudulent accounting needs to be worked on, and where funds not unlimited like city but still substantial, make them put funds into place that are long term investments, to allow for more current spending, so if they want to spend more they need to put funds aside that they can't recover only the club can in 10 years or can be used to cover if they leave and get into financial trouble.
Secondly investment where funds are pumped in from owners with money means far beyond the club, some limitations needed too, to allow other clubs to still be able compete, so maybe City can't spend unlimited transfers, but can spend a lot on club infrastructure and youth development (though might need some controls so they don't make it impossible for any other club to get near any talents), money to invest in affiliated clubs, and lowering ticket prices, things that help the club, fans of the club, and helping boost the league strength as a whole. I would say they should be able spend most of what they spend now, but some should be long term improvements to the club, but it needs to be transparent, so if clubs are pretty much committing fraud to bypass the rules to go past what is allowed they should be punished for it.