I personally think that CGI should be restricted to use in situations that live actors are incapable of performing. Flying scenes, other extreme stunts, over-the-top monsters (Samhail in Hellboy, for example). Use CGI for severely cost-prohibitive effects and scenery. Stuff that would otherwise break your budget. But to replace real actors with CGI and try to pass them off as real (like what Pacino's character does in S1m0ne) is just wrong. It's called laziness.