Look, anyone's judgment could be clouded by Jeremy Peña's 2022 postseason. Because his 2022 regular season wasn't anything to sneeze at, certainly nothing to indicate he was the heir-apparent to Carlos Correa, absolutely nothing to indicate that there was an ALCS and World Series MVP coming the next month.
Sure, he had 20 doubles and 22 home runs as a rookie. 149 other MLB players had done that. Two other guys did it in 2022 alone (Julio Rodriguez and Bobby Witt). Five dudes had done it in 2021. Eight guys did it in 2023, including the Catcher Who Can't Be Found Yainer Diaz.
Peña also struck out 135 times in 558 Plate Appearances. His 24.2 K% was the 24th-highest in MLB among 99 players with 550 PAs. 13 of those players racked up less than Peña's 3.4 fWAR. It was fine. Correa hit .291/.366/.467 with 24 doubles and 22 homers, a 138 OPS+ to Peña's 102 OPS+ thanks to a .253/.289/.426 line. Again, fine.
In 2023, however, Peña seemed to have taken a step back. Maybe it's a sophomore slump, maybe it's the respect that comes from hitting .345/.367/.638 on the Astros' way to an 11-2 World Series run. Peña had a hit in 12 of the 13 postseason games. He hit .500/.529/.688 in the World Series, including a 3x4 HR/2RBI night in Game 5, a 3-2 Astros win over Philadelphia that pushed the Phillies to the brink.
But it's hard to look at that postseason as a stepping stone to a breakout 2023 (as though breaking out in the 2022 Postseason isn't enough), because that didn't happen. The following stats come from FanGraphs:
Barrels, 2022/2023: 38 / 18
Barrel%, 2022/2023: 9.6% / 4.0%
Soft-Hit%, 2022/2023: 16.1% / 15.1%
Medium-Hit%, 2022/2023: 55.4% / 54.9%
Hard-Hit%, 2022/2023: 28.6% / 30.0% (StatCast disagrees, saying Peña's Hard Hit% dipped slightly, from 36.2% to 35.1% in 2023.)
Peña's Groundball Rate jumped pretty significantly, from 46.4% in 2022 to 54.3% in 2023. It seems as though Peña was stinging the ball a little bit more, sort of: his Average Exit Velocity in 2022 was 88.1mph. In 2023 it was 88.0mph.
Where some of his issues stem from are in his Launch Angle. In 2022, a year good enough to finish 5th in AL Rookie of the Year voting, in which voting is tabulated prior to the postseason, he was averaging an 8.7° Launch Angle. In 2023, it dropped to 5.4°.
He's hitting the ball about as normally - over the course of a full season - as he did in 2022, though Peña was more selective and, as a result, got a little better at making contact:
Swing%, 2022/2023: 54.7% / 52.9%
O-Swing% (outside the zone), 2022/2023: 41.0% / 38.3%
Contact%, 2022/2023: 71.4% / 73.8%
He's making better contact, but at a worse angle, and with a lot more ground balls.
HOWEVER! On July 25, Peña went 1x4 with two strikeouts to lower his OPS to .653. In the 59 games following that one Peña hit .313/.379/.402, albeit with a .379 BABIP...which has always been on the higher side for Peña. His .298 BABIP in 2022 - while completely normal for a Major-League hitter - jumped to .323 in 2023, and almost matches the .325 BABIP he posted in Sugar Land in 2021 (and is actually way under his 2019 BABIP of .357 at Low-A and .383 at High-A).
But: From Opening Day to July 25, Peña's BABIP was .277. From July 26-October 1 that jumped to .391. A .391 BABIP in a week is just fluky. It's hard to be fluky for 60 games. From August 8 - the beginning of the first Baltimore series - to the end of the season, he hit .317/.375/.410 on a .392 BABIP.
I'm not buying the "he traded power for contact" argument, because his contact was fairly consistent, there wasn't a drop-off in home runs to create a higher contact rate from 2022 to 2023. The home runs just...dropped off, because he hits the ball on the ground a lot more. But it could certainly be that Peña's "regressed" back to the mean of the ball finding holes more often than not.