Hi John Aquila and all who have responded,
John you asked about what could Franz have gained by making a power play. He already was on the governing body after all.
My answer is as follows: Just before Rutherford died he split the power of the Watchtower into a triumvirate: Knorr was the head with administrative power, Franz got theology and Covington legal.
By the late 60's Covington was a washed up drunk and so after Knorr died in 77 all power now concentrated in Franz. Interestingly Knorr died two years after the failed 75 prediction just like Russell did in 1916 after the 1914 failure (For comparison see William Miller). I don't mention Rutherford because he made a special plea with the 1941 prediction: 'Save me Jehovah I'm dying of cancer' (That man had no shame). However Frederick Franz was actually fully responsible for the 75 prediction and he ended up with the Kingdom.
I would argue that Raymond wanted to split the power up again so that he would get theology. His reasoning I think would be something like this: Well uncle you really botched things up with 1975 didn't you? Isn't it time somebody (a younger man) took over that knew what Christianity was actually all about? You might have been good back in the day, but after Knorr gave us free reign on research, we're (me and Dunlap) every bit as good at theology as you ever were. As a matter of fact we've surpassed you.
Frederick's response: Oh really?
Footnote: After Raymond left Watchtower HQ who did he give an interview to? The NY Eagle who was the traditional press foe of the Watchtower in NY? No, Time magazine. Raymond, you sly dog you.