the only hitter I'd say was better during Jackson's career was Cobb and maybe Speaker, unless you count Ruth and Hornsby. But Ruth only had two full seasons as a position player during Jackson's career and Hornsby's best years came after 1920.
Yeah Shoeless had a very brief career, but he still managed over 60 WAR despite having only 5694 PA. He finished in the top 10 in WAR eight times and had nine seasons in the top 10 in OPS+ (all top 5 finishes). I think his career is HOF worthy, especially if short career guys like Kiner are in.
of course, there's the whole Black Sox thing...