We are obviously just creating noise in the Internet echo chamber here, but I have a few comments:
1 - On an operating basis, any such developmental league is relatively inexpensive in terms of player cost. This is because minor-league baseball players are typically paid a very low in-season salary, less than $2000 per month at the low levels. Such a system does, however, including annual outlay of signing bonuses. Such a system could also possibly include, as I stated things like costs of housing players.
2 - While it's easy to ask whether a mandatory year in college is truly a downside, you are talking about an impoverished population forgoing a year of earning power. That's money that could change their lives immediately. The students are forced to go to college for one year, when they could already be helping their families significantly.
3 - I worked in minor-league baseball and worked closely with players for five years. It takes tremendous maturity to succeed as a 19 or 20-year-old as a professional. There was no rule or no common background that determined whether they would succeed.
4 - The NBA already has a leg up on MLB, because the NBA has established international draft procedures.
5 - Baseball's draft has restrictions. There are caveats, but basically 1) you sign out of high school, or 2) you sign out of junior college, or 3) you play three years of major college ball. If the NBA gave a no college or minimum two years college option, I think it would be good for the college game as well. You'd have college stars for two years, and you'd have a better quality of play because players would be in their systems longer.
6 - if anyone wants to help collaborate on the business plan to Adam Silver, I'm open.