re: Was Oregon State’s first baseball title a major surprise?

You can't look at it in isolation as a Northern school.
Oregon State like Oregon recruits California like all Pac-12 schools.

Michigan is a bigger surprise because Oregon State played in the Pac frankly and had Cali players and had to meet the level of their Conference competition which has won the most CWS titles.

Michigan is probably not recruiting the West or South to any degree Oregon State recruits Cali just like in football.

The bigger surprise was Oregon State's rise under Erickson when the Beavers had been a dumpster fire for all of their history.

Being in the Pac and facing that stiff competition and history, getting California recruits, etc. It's not a leap to believe that a NW school could become a baseball powerhouse.