There is no answer to the question "what is a MiLB player worth."
But I would love to see something that resembles more of a true marketplace that the current system allows, given that MLB has an anti-trust exemption, and the MLB players have exclusive rights to bargain for the pay of MiLB players.
That ain't a recipe for a market.
So, I would like to see no draft, but a cap on signing bonuses for each team, based on where the team is in the draft order.
Also, no collective bargaining contract. Let each player negotiate for the terms. A big bonus might involve a six year commitment, and also get a good monthly salary. Some players (the equivalent of today's undrafted) might sign for a one year commitment, no bonus and low or no monthly pay, just to play and prove himself. Then renegotiate the next year with whatever club will give the best deal.
That is the only way to answer what a player "deserves" - and it will be different for each player.
Mr.Kremer, good calls in this one.
From the NY Times on Marvin Miller (who IMO may be the most important sports figure in the last 50 years) following his death:
In July 1976, the union and management agreed on limitations to free agency: a player would need six years of major league service before he could seek a deal with another club. That accord seemed like a concession Mr. Miller did not need to make. But he concluded that limiting the stream of free agents would fuel the ball clubs’ bidding wars.
So it seems Marvin Miller who was always the smartest guy in the room would have agreed with you and made a better deal for the players. As you point out it would certainly make for a fairer system on a pay for performance basis. Also there would not be those albatross 7 and 10 year deals being made.