The database I use now has 55000 players, 15 favourite leagues, and custom data for all national players in all continents. This gives:
1) OK game speed three stars. (my computer is 4,5 star)
2) Chance of exciting regens from flavour countries all over the world, but still not too many players from each country.
3) Active transfermarket with 15 leagues.
4) Many enough scouts and personell to hire.