With 3" levelers on the back legs that are all the way up, while the front levelers are all the way down, I also wondered if maybe the game is set up with too steep a playfield angle to play as it was intended.

There are a pair of miniposts located at the base of the outlanes with rubber donuts on them. There are two general diameters of those donuts available, one small and one large. You might try installing fresh rubber donuts on the minipost to get a better kick toward the middle when the ball comes down the outlane with some velocity.

Fresh coat of wax was a good suggestion too.

Thanks Damoib. Good info and saved me from having to dig out one of my Gottlieb parts manuals.