Sonny Corleone: JimBo
Both were flamboyant. Both were given to rash decisions. Both had some success (JimBo won division titles in 94, yes, I am counting 94, and 95) Sonny took out Bruno Tataglia and gave the OK to Michaels plan to eliminate the Turk and the cop. Both of their stints in charge ended up badly.
Also, I am told that in an early draft of the book, Sonny also wore leather pants.