Stoicism was the closest I got to converting one of my best friends to Ringo. He loved it for all of the reasons you pointed out but then was disappointed at other SS tracks I played saying it was too "Alanis Morissette does J-pop". He doesn't like Alanis Morissette.
I think my best bet was to get him to like KSK, which is a hard task as it is hardly the most instantly approachable album -- particularly to somebody that doesn't listen to "foreign" music -- but once he sees the genius behind it without instantly classing it as generic (an impossible thing to label KSK), he'll have no problem working backwards and seeing the quality songwriting on SS and MM. I gave up 2 years ago though