Just have a look at what has happened to every club after he has left them ...
Broncos went backwards
Dragons fell into a heap
Knights currently in a heap.
If he comes back it would likely only be 2 or 3 years before he retires. then when he leaves again we are in the same position of trying to replace him.
IMHO, we are far better off finding a coach that will be with us long term. someone who isn't afraid to make the hard decisions. someone who top players want to play for (or will be that person). Someone who can restore the club to its rightful place as a powerhouse of the competition, someone who can turn us into a consistent premiership threat once again.
Now, i don't claim to know who that person is, and i certainly don't believe that Griffin is that person. but i do know that Bennett is not that person either. Bennett is a short term option not the long term option we need to be searching for.
However, if the club's back office or structures need a clean out, then he can do that in the football department just as easily, while being a mentor for our new coach (should he need one).