I haven't played this game a whole lot so I'm still learning.

In a recent game.I had my best base stealers get on 8 times during one game and despite an A+ arm catcher rating from the opposing team, they didn't even attempt one steal. Even though I had them set for at 5 and put on the highest level of aggressive running.

We have a good pitching, baserunning and decent at getting on base team, but not a lot of homeruns in a pitchers park. I'd rather take my chances getting thrown out 40% of the time by a good catcher, than relying 3 hits in an inning. And especially in a game where there will be a lot of 2-1 and 3-2 games.

Why does WIS need to override my settings?

A+ arms are a range of CS%. Baserunners will attempt less against better arms than against weaker arms. With A+ arms, that’s also true. If a very strong A+ arm, they can basically shut down attempts altogether.

more details can be found here: https://www.whatifsports.com/devchat/devchat.asp?chatid=14#1430

Also note that baserunning aggressiveness has no effect on SB frequency. That setting is used to determine how often baserunners will try to take the extra base (e.g. 1st to 3rd on a single).