Sure every pitcher has his bad outings... that's not indicative of his career.
Jamie Moyer is cut from similar cloth as Blyleven, career is mostly about numbers from longevity... not dominance at the position. Moyer is not in same discussion as Morris.
Tanana was dominant but unfortunately got hurt fairly early on and was never the same after.
Viola I've never really studied much... Great pitcher for sure.
Langston serves my point well... good numbers but never played for winning teams... better "WAR" than Morris? So be it. Did he ever even appear in a post season? You can have WAR, I'll take Morris.
Saberhagen was a phenomenal rookie winning WS and Cy Young but career mostly declined after. He pretty well stunk in post season for Red Sox.
Dave Steib was another fantastic pitcher and great career. But again, did nothing in the post season.
I'm not saying post season and championships are a hard requirement for HOF, but it absolutely matters to me. The best players do it on the biggest stage. Especially pitchers. It's no accident that Morris pitched for so many winning teams and in so many meaningful games. HOFer.