So, in the spirit of giving you some sort of answer to your question, and acknowledging that you have expressed frustration elsewhere with not getting a response, I'm afraid I just don't have a good answer for you.
In my fictional league I have not experienced any concerning oddness with draft pools, other than some year to year variances which tend to balance themselves out over time. I do use feeder leagues- College, JuCo, and High School.
Now, in general I think it is true in both real life as in OOTP that there will always be fewer players entering drafts who are legitimate prospects at premium positions like shortstop and catcher and center field and second base, etc. That's part of what makes them premium positions.
But as I do not sim and play out all of the games for my team, I am only now in the early stages of the 22nd year of the league, so I can't promise I won't run into problems in time.
Hopefully someone who has a better answer for you than I do will respond and offer actual assistance.
Edit: I should probably add too that some of the people who might be in the best position to answer your questions- Developers and beta testing team members- are pretty darn busy right now so it might be a tough time in the cycle of development to get as many answers as you might expect at another time of year.