Coppola,
Believe me, no one wishes that Pacino would be in a GF4 more than I, but I really don't think it would work. I think it was undertood that Michael died in GF3,

and starting another GF with him really alive, would be unbelievable. (Something like Pam's dream in the tv show Dallas, where next season it was all a dream....

) If there was a believable way to do, I'm for it though!!! I just don't see how!!!
ps You sound like a Pacino fan too!!!!!
