Mike Shildt didn't play pro ball. What made him so special? He came up through the Cardinals' organization, starting as a scout, seeking a chance to coach, and growing from there -- gaining trust of the people around him, the players entrusted to him, and responsibility at each step. He was placed in charge of the minor-league spring training, and that put him in contact with Tony La Russa, who took on a mentor role to him. Shildt did a lot of listening. Used his assignments to prove himself -- his ability, his commitment to the organization, his grasp of the job, and his willingness to adapt, adjust, and work with the front office and what it was trying to accomplish. So, part of what made him special was he's homegrown, coming from doing the job of manager, not of the ranks for former player.
There are a lot of similarities with Jeff Albert. He was in the Cardinals' organization. He impressed people who would later higher him by his questions, his work with younger hitters, and his grasp of modern tech and modern hitting philosophies. He went to Houston, where he was exposed to and part of one of the most advanced teams in the game when it came to analytics. There was a time not too long ago when Luhnow's Organization was lauded throughout the industry for pushing the envelope of analytics, finding edges, every edge (yes, even edges against the rules), and being open to new ways to do things. The Cardinals felt they were falling behind as an organization when it came to hitting tech and hitting philosophy. Start there: They did not have the widespread tech use for their hitters that was becoming commonplace in the game. Albert was comfortable and confident with the tech, and he had a plan. His plan and his familiarity with the Cardinals were attractive to the Cardinals who wanted to create a total-organization overhaul of the hitting approach and infrastructure. The job they had open was hitting coach at the major-league level. They turned to Albert to fill both.
Looking for batting average or OPS as a sign of an ability to coach is as irrelevant as looking to how many shutouts a pitching coach threw or how many All-Star appearances at any level a manager has. There are many ways to learn the game, grow in the game, and become an instructor in the game. Wearing a mask to work helps, for sure. Absolutely. It's a great head start. But it's not the only view that gets you there.
At least, that's my experience.