Already some discussion about this. I think the league would rightly expect some players to opt out after getting drafted - their orgs might tell them not to play anymore.
"Jackson alludes to the fact that the league expects some players to pull out of the league after being drafted, noting that “after the draft, we’ll be able to take some kids — some of the seniors and some other guys looking to get those free-agent opportunities and put them in that mix.”
But it is an MLB organized league so is it much different than these kids going to short season, or whatever, after the draft?
And pre-draft, you really would not expect pitchers who have just had a full college season to come in and throw but you might instead see mid-round arms looking to make an impression, guys who were dealing with nagging stuff all season and did not throw a lot during their college / high school seasons, etc.
I dunno, more data can't hurt. This is probably just replacing lesser showcase type things that some of the players do anyway so who knows how much more baseball it would even be for them.
It would be cool though to see a bunch of first and second rounders immediately after they have been drafted, in a league that's broadcast through MLB.tv (or whatever) with good camera angles and some of the newfangled tracking stuff.
One issue historically with MiLB and the promotion of MLB is how remote and mysterious and inaccessible baseball is when it is further away from the big leagues. You can't watch instructs, you can't really watch most minor league teams (at least not on good camera angles). Maybe part of what MLB is trying to do with the MiLB reforms and this is to elevate the minor leagues just a little bit - decrease the sheer number of teams but create a more concentrated and watchable product from the time players enter the system. This type of league, with heavy investment, could really promote that end.
Imagine if a few weeks after the 2020 draft we could have tuned in to watch Austin Martin dig in against Nick Bitsko (RIP) in HD?