Lighter weight, slower slugs will kick less. Remington has their "Managed recoil" Sluggers, which are 1oz slugs with a lower velocity, but may only reach out to about 75 yards effectively.
Why you would want to use slugs at all for a home defense shotgun though is beyond me, the point of a shotgun is a spread of shot.
But I hear you. I recently had to diagnose a problem with a guys 870 at work, he said it was wildly inaccurate. I boresighted it, and he asked me to shoot it. Pulled a group fine, but my shoulder hated me after putting some 300gr Hornady SST's down range.