Bryant: Rookie 30.6%/MVP: 22.0% last year: 19.2%
Rizzo: SD: 30.1%/1st with cubs: 16.8% after that he has been one of the best hitters in baseball.
Contreras: Rookie 23.7% sophomore: 22.9% That is a respectable rate.
Baez: 41.5%/30.0/24.0/28.3 He went backwards last year with more playing time. He kinda concerns me.
Happ: 31.2%
Schwarber: 28.2/40.0(5 AB's)/30.9% (something to prove this year)
Russell: 28.5/22.6/23.6% like Contreras respectable
Heyward has pretty much around 20% or less his career.
Zo around 15%
Almora: under 20% so far.
You're not really using stats effectively here. Just because Bryant cuts his K rate doesn't mean much. What you should be doing is comparing players vs competition closer to their age range. That's why I brought up his minor league numbers. If you do this you can see players who are more likely to improve. For example, you bring up Rizzo but Rizzo wasn't a high k rate guy in the minors. He k'd 389 times in 1913 minor league PAs or a 20.3% rate. Russell was 230 in 1090 or 21.1% That's different someone like Baez who k'd 430 times in 1693 PAs or 25.4%. Happ was 223 in 978 or 22.8%. Schwarber was 141 in 665 or 21.2%.
The vast majority of players will eventually settle into their minor league rates. Bryant is an exception here but that's largely because he made a mechanical change to fix a hole in his swing. More often than not most players can't do that. It's why he's an MVP candidate year to year. But as I've literally been saying for years, Baez isn't suddenly going to turn into a 20% k rate guy unless he does find that sort of change. Likewise, Happ isn't going to be an above average K rate guy. That's not something that will kill him at a 23% rate or w/e but it's not what you want batting lead off.
Also I don't agree with your definition of "ideal leadoff." It's more than just OBP. An ideal lead off hitter yes gets on base but in my view an ideal lead off hitter makes a pitcher work. You want someone up there who let's the 2-4 hitters see what a guy has today. Is his breaking pitches sharp? Is his fastball lower velocity...etc. What I want is a guy who can sit there with 2 strikes and foul off pitch after pitch if need be until he gets something he can use. If you make the starter throw 6-7 pitches before you get on or get out that does a lot of damage to him because then he's just worked his tail off and runs into Bryant and Rizzo which isn't a fun time. Someone like Matt Carpenter or Anthony Rendon is just great at that sorta shit.
That in my opinion was the issue with Schwarber there last year. Schwarber was near the league lead in pitches per plate appearance but with 2 strikes he couldn't do much. For example, Schwarber averaged 4.34 pitches per plate appearance compared to 4.37 for Rendon and 4.44 for Carp. But there's a clear difference in how difficult those hitters are at the top of the line up to what he was doing last year. For what it's worth, Happ was 3.92 which was 137 of 287 among mlb hitters with a min of 300 PAs. So, like Schwarber last year he thus far in his career has struck out at a high clip and worse than Schwarber isn't seeing as many pitches.
I don't see Happ ever being much more than a .330-.335 type OBP guy. He looks like he may already be at his base walk rate. It was 7.3% in AA, 9.5% in AAA and 9.4% last year in the majors. So any improvement to his OBP is going to have to mostly come from his batting average. To get into that .360 OBP range you're talking about him basically needing to hit .290. Realistically he's probably only a .270-.275 hitter at best.
All things being equal, like I said I think he's ideally your #5 hitter. He has enough power to drive in runs from higher OBP guys. If you wanna do the whole thing where you put your best hitter #2 you could move him up to the 4 slot. But I think we're talking about a .270/.335/.475 type hitter.
