Carroll went 16 because he was short, his talent was always there.
Power is one of the easier things to project, and it got better with statcast data. Now maybe a team looks at him and they think with a swing change you can unlock more power.
Carroll coming off his 21 year old season had a 55/60 Raw power grade and 50/55 game power (present/future). Schanuel coming off his 21 year old season is 30/50 Raw power, 45/45 game power. 50 is league average. Schanuel’s 90th percentile EV is 106 with the major league average is 103.5. That sounds decent until you take into account he was in a bad conference with a metal bat. His plate skills are intriguing, but the bat really has to play at 1B and without the power it makes it really hard.
Well, Termarr Johnson is 5’8 and he went #4 overall last year. Recall a guy named Corey Patterson (5’10 same as Carroll) and he went #3 overall. Put another way, if the projection is very high, the player can still go very high irrespective of height.
DBacks made a good call on Carroll and that is based mostly on good scouting and good luck. The notion that “power is one of the easiest things to project” with a mid-round-one guy in the draft is overstated——nobody really knows who will hit, power or otherwise. Sure, when a guy has a few years as a pro already, as you note with Carroll years after the draft, you can have a much better idea although still unpredictable. But, on draft day? All a big question mark and hope for the best, except for maybe the occasional elite guy(s) that everybody loves.
Maybe Schanuel at #13 is a poor idea. I have no idea. My point about that is if Cubs pick him at #13, it’s because they are seeing something that the EV data is perhaps not fully capturing and they really like him and they have infinitely more expertise on the matter than you or me. Maybe that would turn out to be a bad pick or maybe a great pick. That turns on scouting and luck, not because power is easily projected or not projected.