The cost is prohibitive to put the ball across all minor league levels. Frankly, one positive thing about putting the MLB ball into AAA is making AAA relevant again in development. For the last 10-15 years, teams had begun to move away from using AAA as a legit development stop and begun using it more as a place to harbor quad-A type guys and extra arms that were just off the 40-man for use as needed with the big league club if an injury outbreak were to occur. Now AAA is a legit stop that you need to see both hitters and pitchers make in their development. With pitchers, the outcome is obvious. One tremendous example recently left my favorite organization, so I got to have plenty of view on this. Kolby Allard was a prime draft candidate coming out of high school before back issues hurt him in his senior year and took his velocity from mid-90s in showcases before his senior year to low-90s his senior year. He was handled gently by the Braves and had to have back surgery early on with the team. Once he returned from that, his velocity was significantly down, often pitching entire games without topping 91 MPH, working primarily 88-89. That sort of pitching requires absolute precision or tremendous movement in the minors to succeed, but it requires BOTH in the majors. Allard hit the majors last season for a quick debut, and the first introduction to the different ball was obvious. He was hurt badly without a fourth pitch that he could command with movement. He spent the offseason working on a cutter, and while he's added another tick or two of velocity (sitting 90-92, touching 93-94) this year, he's spent the whole year in AAA and seen his improved arsenal contribute to a high-3's ERA, which is currently a top-5 ERA among all qualified AAA starters this season. If I'm Texas, I'm much more confident in his ability to produce as a #3/4 starter in the majors now after showing that performance in AAA with the same ball he'll see in MLB. For hitters, a ball that explodes off the bat can lead to some bad habits. While we know of the launch angle movement among many organizations, the nuance to that is significant across the game, and many players in AAA this season have notably gone for an all-or-nothing approach with their swing after finding power for the first time this season. It has allowed other hitters to show an ability to take controlled swings and cover the strike zone well, even with additional production from their natural and/or optimized swings without over-compensating for the ball. Tim Locastro of the Diamondbacks is a great example of a guy who hasn't put together a monster home run season, but he's shown an ability to generate average or above-average power without changing his swing mechanics due to the ball, and his previous excellent zone judgement and plus speed now play up into a big league starter. Josh VanMeter of the Reds is another great example of this. He had the Dustin Pedroia profile down well, but he was just a half-grade below Pedroia in every tool, which really shows the fine line of a quad-A guy and a potential All-Star as far as second base goes, but with the new ball, he's essentially playing as prime Pedroia in output. Even with the glove still that tick below, he's able to find a spot in the lineup with that production. In general, I'm not sure that spreading the ball across all minor league levels would actually be a productive thing. There does add a dimension of achievement in climbing the ladder, getting a chance to play in semi-MLB conditions once you've achieved AAA. That's just my pair of Lincolns, though.