I wouldn't go as far to say that he was regarded as a "joke" -- certainly everyone knew he was responsible for killing Sollozzo and McCluskey -- but he wasn't held in the same high regard that his father was, either.

Even within his own inner circle there were doubts. Clemenza begged to start his own family, and Tessio, of course, ultimately proved to be a complete traitor.

But after he killed everyone off, I would imagine it was a different story.