If there's one thing Hollywood botches time and time again, it's the prostetic makeup of disfigured characters... Jigsaw's face is supposed to be a literal patchwork of scars and skin.
In Game of Thrones, Tyrion's facial scar removes his nose entirely, leaving only a hole in addition to his uneven legs and mismatched hair color. Not exactly in line with Dinklage's roguish good looks and charm.
In Mortal Engines, Hester gets cut in the face as a child, costing her her left eye, a missing nose and a permanent drooping right jaw. What movie-Hester got was a scartissue not that different from Tyrion.
If you're building a character, removing a visual representation of the mental scars that character possesses insults the source material and inhibits the actors ability to portray that to the audience. CGI can do what makeup cannot, we have seen that often enough. But we've also seen how great a good makeup session can be, so Jigsaw is just a letdown to everyone, hopefully even to Barnes.