1970 AL Jim Perry
Perry won a major league-best 24 games but didn't lead the league in anything else and wasn't even worth four wins. Third-place "Sudden" Sam McDowell was worth more than eight, which makes sense given that he pitched a league-high 305 inninngs with a 2.92 ERA and 304 Ks, most in baseball. Jim Palmer, who finished fifth, pitched just as many innings and had a superior ERA (2.71, though their ERA+ was an identical 134) along with five shutouts, which led both leagues. Since most of their numbers are so close, I probably would have gone with McDowell due to his huge strikeout advantage.
1974 NL Mike Marshall
To be fair, Marshall turned in one of the best seasons a reliever has ever had. Iron Mike set the record for most appearances by a relief pitcher (106) and threw more innings (208.1) than your typical modern day workhorse. Even so, B-R values his performance as worth only 3.1 WAR. His season also loses some its luster considering the second, third, and fourth place finishers averaged 290 innings pitched between them. Runner-up (and Marshall's teammate) Andy Messersmith would have made a fine choice since he threw 84 more innings with the league's best WHIP and an ERA that was only marginally worse (2.59 to Marshall's 2.42). The most deserving candidate was Phil Niekro, who placed third, because he led the league in innings (302.1) and complete games (18) with a better ERA (2.38--second in the NL) than both of them. That quantity/quality combo translated to almost eight wins above replacement, making him the league's second most valuable pitcher behind only Jon Matlack.
1977 AL Sparky Lyle
With a 2.17 ERA, Lyle had the best season of his career, but as a reliever he was only good for 137 innings. Runner-up Jim Palmer logged an AL-best 319 (thanks to his 22 complete games--most in baseball) with a 2.91 ERA, and was thus twice as valuable per bWAR. Third-place Nolan Ryan was arguably better that year. He completed just as many games as Palmer (but threw 20 fewer innings) with a better ERA (2.77) and 341 strikeouts. '77 was also Ryan's best season according to bWAR, of which he produced 7.8.
1978 NL Gaylord Perry
Perry paced the league in wins (21) and winning percentage (.778), but didn't lead the NL in anything else and was worth 4.3 bWAR. Burt Hooton, Vida Blue, and J.R. Richard, who finished second, third, and fourth, had nearly identical seasons in terms of ERA, innings, and overall value, which makes one wonder how Perry won the award in such dominant fashion (with 22 of 24 first place votes). The trophy should have gone to Phil Niekro, who finished a distant sixth. Voters probably held his 18 losses against him, but they should have overlooked that, for Niekro threw more innings (334.1) than anyone else in baseball while maintaining a 2.88 ERA, right in line with Perry's 2.73. Throw in his 248 strikeouts (second only to Richard's 303) and he was baseball's most valuable player worth 10 bWAR.
1979 NL Bruce Sutter
Sutter racked up nearly five wins above replacement: an impressive accomplishment for a reliever. But he barely pitched 100 innings. Third-place J.R. Richard tossed nearly 300, and with a major league-best 2.71 ERA to boot. He also fanned 313 batters, most in baseball, to go along with his league best K/BB ratio, K/9 rate, and H/9 rate. Winning the two most important legs of the pitching Triple Crown should be enough to do the trick, but voters preferred his teammate Joe Niekro, who finished second largely because he won a league-high 21 games (same as brother Phil).