" . . . the wiper arms move much easier on a deceleration as compared to an acceleration. Maybe this is normal on a vacuum running setup."
That is correct - almost no vacuum to the wipers when accelerating; and, rapid wiper-action otherwise (when decelerating or at idle).
When you need wipers in a rainstorm at higher speeds, you learn the gas-pedal up-down dance-step.
As I dimly recall, there was a vacuum-canister option/accessory to help to avoid/minimize this.
