Evans was ahead of his time offensively. Back then he was just a .270 hitter with a bit of pop but at his peak his OBP was consistently around the .400 mark (career .370 OBP), he was arguably the best defensive RF in history, hit 385 HR's, logged 2446 hits, and had career high OPS + years of 162, 156, and 148 (in 1981, 1987, and 1982 respectively)
When you combine his marginal-to-borderline offense to his legendary defense, he sniffs the edges of HoF worthiness. That plus his role in the 1975 and 1986 pennant runs might put him over the edge in some eyes.
It's very possible that if he'd played in an era where OBP was en vogue he'd be in. He at least deserves the kind of consideration Andre Dawson got/is getting. He at least should be given an honest look.