McGwire's 'one dimension' was Hall-worthy
If by "one-dimensional" you mean "all he did was hit home runs," then no, that's not precisely true. McGwire drew more than 1,300 walks, and eight times he ranked among the top 10 in walks in his league. He didn't strike out particularly often. He never led his league in strikeouts, and finished in the top (i.e., bottom) 10 only twice. McGwire was not the all-or-nothing slugger we might see in our mind's eye. Yes, he batted .201 in 1991, his worst season, and .187 in 2001, his last season. He also batted .289 as a rookie in 1987, .312 in 1996 and .305 in 2000. McGwire's .263 career batting average was dead-on with his leagues' averages (one of which includes pitchers hitting, obviously, but still ...).
Here's the bottom line: The two most telling statistics in baseball are on-base percentage and slugging percentage. You probably won't be surprised to learn that McGwire led his league in slugging percentage four times. But you might be surprised to learn that he also led his league in on-base percentage twice.