It should be continued in two ways
Either an all round remake or a a complete final.
As for the second option. The story could easily bring a duplex line. It really should find a person ( character ) that can put the story to ending. Still remembering that Hoffman telling Strahm ( and now my legacy becoming yours ) before his assumed death. Well, what I mean duplex line carrying the dead Hoffman and his legacy and Jigsaws unfinished and revealed game. ( that Dr Gordon could easily carry on ). Something like that.
Or just a simple remake that could show us how things happened in a detailed way.