Here's a question: Why is there still a Skynet-versus-humanity future? At the end of T2, Connor threw the microchip and arm (remnants of the T-800 that chased Sara in the first film) into a vat of molten steel, destroying it so that humans in the present could not study it and eventually built Skynet. That was supposed to mean the end of the story. So I guess we're seeing John from "already-fucked-future" timeline. Um... Right?
As for my opinion of this film: It looks stupid. A real predictable, showy, can't-believe-they-greenlit-this, embarassing, blasphemous shitscream. Its letdown level can only be rivaled by Transformers. Way to shit on the classics again, Hollywood.