Yes, roster needs. Depth at each position, etc. There are a bunch of things.
Then there are more subtle things I've learned, some examples:
- English players rarely leave England to join clubs La Liga, Ligue 1, Serie A or Budnesliga
- South Americans are twice as likely to join clubs in Spain or Italy. Very rarely do they go to Germany. Italy is 3x as likely a destination than the EPL for South Americas. Spain is 2x more likely than the EPL.
- Germans almost never to go Spain
- The average PES overall rating for a player transferring to a top 3 EPL table club is 81. The average is 75 for a team in the bottom half of the table.
- Half the players leaving the EPL to join Ligue 1 clubs are French nationals
These are just some examples. But there's certainly some things around team prestige, budgets (these aren't even close to realistic), player prestige, player age, etc.....