Too strict financial limitations would just lead the big money whore clubs to leave their national FAs and UEFa and form their own SUPER LeagueTM. Which would be awesome from rich fat owners point of view, no need to let players go with the national team and no stupid transfer windows limiting the endless spending. Participation would be guaranteed every year and no fear of relegation.
I fear that it's not very far in the future, when more and more clubs fall into hands of rich (foreign) owners that have no clue about history and traditions.