Your view seems a little bleek and drags up old problems that have been fixed for years, the 400 hour valve check is only for engines without the hi-chrome valve guides, I cant remember when I last saw one of these.
I cant see how a roller would have any effect of the corrosion on the face of a cam, I think it has far more to do with ease of production, rather than having to produce solid cam follower with a slightly offset face to ensure that it rotates slowly & the
PR department turning it into a selling point.
The piston pin problem has nothing to do with them being ali-bronze, it is due to a step being worn in the bore.......this is becoming a real issue with the O-235 were I have seen failure starting to happen at as little as 300 hours. If you had a piston pin plug break up it is due to very poor maintenance as basic examination of the oil filter will indicate piston pin plug problemd long before total failure.