Bert is a toughie only in the sense that he only played half his career here but that is still 11 years. His win totals while with the Twins are as follows;10, 16, 17, 20, 17, 15, 4 in first stint, 8, 17, 15, and 10 during his 2nd. He was traded during the season in the 7th year of his first stint and didn't leave for greener pastures.
He was vital to the 87 team's success, our first major sports championship since the forgotten Mpls Lakers. He is in the HOF as much for what he did here as anywhere else.
I am old enough to remember the aging nucleus of the Twin's teams he played on early in his career, thus his nearly .500 record. They won 98 games his rookie year then went on to win totals of 74, 77, 81, 82, 76 and finally 85 until he was traded. Many of his losses were low scoring 1 run games as evidenced by an ERA well under 3.00 during 4 of his 6 first season and at or very close to 3.00 the other 2 seasons. The complete game and innings pitched totals he put up were astounding and he still lasted over 20 seasons. He would be a GOD now with those stats.
The Twin's all time pitching stats include those of the Washington Senators so I'm excluding them when I attempt to find Blyleven's place among Twin's pitching records. He's second to Jim Kaat in wins for the Twins, 4th in ERA with way more innings pitched than those above him, 3rd in #of starts, 2nd in innings pitched, 1st in SrikeOuts, 5th in WHIP, again with 1300 more innings pitched than the closest guy above him.
Kaat, Radke and Santana all played for much better Twins teams than Blyleven, yet still trail him in most pitching categories. Kaat only bested Blyleven in number of wins, innings pitched and HR and BB allowed rates per season though he did surpass Blyleven in total Hr's and BB's allowed with all the extra innings pitched.
Kaat had more wins for way better teams, but his ERA and WHIP weren't as good and Bert struck out nearly 200 more guys in roughly 450 less innings. Radke was near him in wins but gave up over 80 more HRs in 100 less innings. Though Radke did walk far fewer guys than Blyleven he still has a higher WHIP of 1.26 vs 1.19 which tells me that Radke was far more hittable. Radke was the quintessential "pitch to contact" guy that the Twins based their drafting on for too many years.
You have to go back to Walter Johnson, one of the all time best ever to find a more dominant pitcher with reasonable longevity in the Twins/Senators organization, than Bert Blyleven. Blyleven is arguably the most dominant pitcher to ever don a Twin's uniform for a reasonably long period of time. Jim Kaat is the only one who comes somewhat close, with Brad Radke and Johan Santana perhaps tied for a distant 4th.
I think yes Bert did enough, and certainly more than any other Twins pitcher, to deserve to have his jersey number retired.