[Syd Thrift]

I think that more than anything else, the biggest thing that affects the draft in 1900 especially but really throughout the early 1900s is the relatively small draft classes. If you're playing with just the major leagues and a reserve roster (which isn't super realistic but OOTP doesn't do a great job with how things actually worked back then because it's very, very far off from modern baseball) you might only have, say, 3-5 rounds for your draft. The game generates draftees more or less randomly so it's very easy to have a big chunk of those guys be pitchers one year (and hitters the next... or pitchers again, there's no balancing-out algorithm going on outside of random chance), and that's going to be exacerbated if you have a small draft class feeding in.

One way to fix this - "fix" this - is to have ahistorical minor leagues with, say, 3 levels and then run a 10-ish round draft (the rule of thumb is, 3-5 rounds per level of minors). That should bring in enough randomly generated players to sort of balance things out most years. It also allows players to progress normally though the minor leagues; the game doesn't really know how to operate independent minor league systems who aren't just trying to snap up any player available (and it especially doesn't know how to buy and sell good players to/from other independent teams and leagues).

Another factor here, although I think it's a small factor, is that if you set the game to create players using the PCMs, it's my experience that it'll create a lot of low-stuff, high-movement, good-control guys who might look really good to the 20-80/stars rating algorithm. As kq76 alluded to, that doesn't necessarily make them actually good pitchers though. The fact that the AI will covet a guy who's essentially, I don't know, Noodles Hahn (a good but not great deadball era pitcher whose stats look potentially eye-popping to an algo set to look at players from the lens of the modern era) is its own issue but in terms of the makeup of the league it's not necessarily game-breaking or anything.