I'd be totally cool with a CGI sequel, as long as the voice talent doesn't phone in their work. Murray's work in the game was noticeably weaker than any of the other talent. The game's got the guy who played Peck, Annie Potts, Alyssa Milano, they even got Max von Sydow to reprise his voice as Vigo the Carpathian. All of them seemed to put more oomph into their performance than Murray did. It didn't matter a ton, since you spend most of the game backing up Winston, Egon, and Ray anyway, and Peter doesn't feature super-heavily.
But based on that, I'd say that a CGI sequel would be just fine IF Murray really is invested in it. I just don't get the sense that he is. The ONE thing (aside from this appearance) that he's done in the last 21 years for GB, and he BARELY made it count. I honestly do not think he's interested, and that's why I don't think they're ever gonna do a sequel.