That's what I would do, and have done in the past.
I have been asking about the addition of real coaches and at least managers in historical setups for some years, but no sound from The Man.
The biggest issue I see is that the real managers that managed the teams the years you start are in with correct win-loss and experience. Never mind that their tactics isn't always correct, but managers that sat out that year and signed the year after will never pop up in the game.
This is like in older version you had a player sitting out one year you start, then he never got into the game the next year he played. This was fixed several version ago so why not put more realism for at least managers.
It would be fun to have some real managers without jobs when you start that are managers you recognize. Now you got even loads of "international" managers that in older days never would make it to a MLB team. Some sort of DB for managers are in (Lahmann) so perhaps we could at least import new managers at any point like players we think is missing. That would almost be enough IMHO
The risk that a fictional managers take charge of a MLB team and run it very different than normal is too big
I also turn of any morale and other stuff. Historical is mostly about what they did score not how they felt and what issue players got with each other. Kind of playing APBA or SoM with cards.
You have to rely on stats a player put up, not mood or emotions (that is also fictional).
I even came up once with Barry Bonds as a very likeable guy
