Many thanks to Luke-OH for his scouting information.
I apologize if this has been posted already.
Baseball America had this to say about Rucker (I swear it is more positive than what I saw from that site immediately after the draft).
Rucker's stuff drew varying opinions in 2019. Some scouts saw a pitcher with very vanilla stuff, but scouts who saw him in other outings saw arm speed and a quality fastball. He’s a 6-foot-1 righthander who spent most of the year in Double-A. Rucker’s 92-96 mph fastball earns some above-average grades. He has a pair of breaking balls and changeup are all fringe-average to average, so he has to succeed with location and staying a step ahead of hitters.
MLB had this part way through 2018
Scouting grades: Fastball: 55 | Curveball: 55 | Changeup: 50 | Control: 55 | Overall: 45 Rucker led the Western Athletic Conference with 11 wins as a redshirt junior at Brigham Young in 2016, when he was one of 16 college pitchers drafted by Chicago in the first 20 rounds. He has exceeded expectations since signing for $180,000 as an 11th-rounder, posting a 2.12 ERA in his first two seasons. The Cubs eased him into pro ball as a reliever and he continued to thrive after they turned him loose as a starter in high Class A last June. Rucker might have the best fastball command in the system, enhancing the effectiveness of a 91-94 mph fastball that reaches 96. He has improved his curveball since turning pro, giving him a solid second pitch. His changeup is more of a work in progress but there are games when it works as well as his curve. After initially looking like he might advance quickly as a bullpen piece, Rucker now is a potential back-of-the-rotation starter. He's not overly physical but keeps his pitch counts down, allowing him to work deep into games. Out of nowhere, he has become one of Chicago's most advanced starting-pitching prospects.
He broke UZR because of his shifting. IIRC they ended up taking out plays that are fielded more than a certain distance away from the usual starting position for a given fielder so Zobrist and a few others wouldn’t get OOZ credit for balls hit in the RF gap as a 3B.
This is from Brandon Bailey's blog. https://brandonbailey1994.com/2019/03/19/how-do-i-top-that/
It mirrors some of the things player development was doing with pitchers in the Orioles system in 2019.
"What I didn’t understand was that the Astros player development staff was purposely challenging me to get out of my comfort zone, propelling me to throw more curveballs and sliders rather than my bread & butter fastball-changeup combo. This new challenge forced me to deal with some failure and adversity; and while no player ever wants to be told that they have blaring weaknesses in their game, sometimes it’s the brutally honest conversations that lead to the biggest improvements.
“We’re not preparing you to have success in the Carolina League,” my High-A pitching coach Drew French explained to me one day after a tough outing, “We are preparing you to have success in the big leagues.”"
I have not studied this topic, so I cannot get specific. However, after having watched MLB operate for many years, it just might be a perceived short term solution to a perceived problem, but I would bet that in the long run it will not help the players. Sure some players salaries MIGHT rise slightly, but there will be fewer players, fewer teams, and less help to local economies as the result of this proposal. Remember. minor leagues are the life blood of MLB.