ISO is good. A high walk rate is good.
I focus on strikeout rates early in the season because it is a stat that does not need as big a sample size to indicate something real has changed. But it is not the only way a hitter could improve.
If you look right now the best offensive teams tend to be the teams with the lowest strikeout rates.
I get the argument you could look at any stat and say, "X stat is low/high relative to league average performance therefore it correlates to better hitting production.
I'm a New Yorker and had to live through the Yankee late 90 dynastsy where all the guys on their team were 'tough outs'. Weren't big power hitters but weren't punch and judy guys either. I get a vibe like that with our current team.