doh! was posting while packs stole my thunder 
Its not his winning % that keeps him out in my book. Its the fact that he only pitched 7 full seasons (30+ games), and 3 partial seasons (16 or less).
But those were some amazing 7 seasons. In 1911 and 1912 he was #1 in Wins Above Replacement for ALL players in the league. And in 1912 he only went 18-21!!!
Every year that Nap Rucker played, his team (Brooklyn) was last or close to last in the NL in batting average and runs scored. He had no support!
Baseball-Reference ranks him #125 all time amongst pitchers. If he'd had another 3-4 full seasons I think he would've cracked the top 75 all time and been a HOFer. But tough to get in w/only 7 of 10 seasons being full.