Yup, it was the whole point. It's because McClory held the rights to Blofeld ahead of EON.
I thought Pleasance was too much of a grotesque
Gray too camp.
Savalas was the best of the offical lot, but even so I couldn't quite believe him.
I could believe Von Sydow was the head of a large criminal organisation.
Von Sydow, The two Bond girls, and Connery are the only things really worth mentioning fron NSNA