#1 - Allow Jordan Walker to get some more seasoning
It is becoming more and more common for elite talents like Walker to skip the Triple-A level and end up in the Major Leagues, but even so, Walker is still just 20, and there is no need to rush him at this moment. The club needs to prioritize his development over all things, and if they think it would be best for him to get at-bats in Triple-A, then that is what they need to do.
Over in their excellent Cardinals' prospect rankings, @CardinalsReek and @KareemSSN noted that as a hitter, Walker still has some room to improve in key areas like Chase% and SweetSpot%, which rank below average compared to other MiLB hitters. Still, Walker does so much damage with the balls he hits, that he is not negatively impacted by those issues as much as the typical hitter would be. But if Walker wants to continue on his elite trajectory, improving these, as well as getting more of his batted balls into the homerun launch angle, will be key for his development as a hitter.
That may feel a bit nitpicky, and it is. Walker is as good of a hitter as we've seen from a 20-year-old and has excellent mechanics that should propel him moving forward. Even so, setting Walker up for as much success as possible is not a bad desire from the front office.
The other area, which could use more work as he progresses, is Walker's defense. Since transitioning to being an outfielder midway through the 2022 season, Walker has been impressive for sure, but he has a ways to go before he maximizes his potential in the field. That's not a knock on Walker, just the reality of the club waiting so long to have him switch positions.
Walker has an elite arm and has already shown that he has a cannon for an arm, and paired with his sneaky good speed (he stole 20 bases last year before being asked to stop stealing to prevent an unnecessary injury), this gives Walker a high ceiling as a corner outfielder in today's game. There is no reason to believe Walker won't be a good outfielder defender, it's just about getting him more reps out in the field.
Should Walker answer these concerns in Spring Training, it'll be very difficult to leave him off the Opening Day roster, It's clear that Walker has talent that the Cardinals' system has not seen since Albert Pujols and Oscar Taveras, but that does not mean they need to rush him. Especially in light of the second reason he won't be on the Opening Day roster.