FakeNewsJnr: Have you ever thought of creating a Historical league instead of a fictional league, enabling the OOTP development engine (no recalc), increasing the Talent Change Randomness from default 100 to 150 or higher? This is the way I play and I think it's awesome.
I started in 1981 as the Yankees GM. Every player on every team was exactly as it was in real-life on opening day 1981, but from the first pitch thrown in my Historical league, an entirely new history is being written. I don't use historical rookies/lineups or anything like that. I want my new baseball world to be unique in those regards.
Each MLB team will have the real minor league teams they had in real life with the real prospects just like in 1981. There will be a first-year player draft every December 15th and it will have all of the real players who were in the draft year after year, but because it's a new history being written, players can end up anywhere based on the draft order.
When 1981 started all of the players in my universe were rated legitimately based on real-life stats/performance, however, not every real-life Hall of Famer will have a Hall of Fame career in this universe. They might get injured and never fully recover. Maybe that real-life HoF pitcher ends up on the worst team in this new universe, never gets run support, and ends up with not so impressive statistics. Anything is possible.
For the most part, each player will initially begin with as much current skill and potential as they did in real life, so the odds are that Babe Ruth is going to be a very good to great ballplayer, but what if he never got traded to the Yankees in your universe?
In my current universe, for example, Chipper Jones was the #1 draft pick in 1989. By 1991, he was written off by the team who drafted him. His ratings were in the toilet and he sat on the free-agent list, unsigned for a couple of weeks before I grabbed him. I put a ton of work in him and while he'll never be like the real-life Chipper Jones, he is now the starting 3B for the Toronto Blue Jays in 1995 and doing well. I traded him last season.
I think it's so much fun to see the real player's names but on completely different teams. A lot of players in my universe play at the same exact level as they did in real-life...So, it's not like every big name stinks in my world and vice-versa...