Well, if you ever try to do a roster set, you'll see that as the season goes on and players are moved around, it could be like have a full time job keeping track of where everyone goes. The game will fill in bullpens once you start a season. In order to export rosters, you minimally have to have 5 starters and a closer. Yes, I focused on MLB teams. But, I didn't just moved them around. I spent dozens and dozens of hours revamping pitchers and fielders in a variety of areas so as to try to emulate the real teams as best as possible. I even re-imported players that were missing. This is one of the main reasons I won't be doing rosters any longer (at least not for this site). Besides a handful of people, by and large people don't appreciate what goes into it.