I wonder if Skynet had some humans on their side. As ridiculous as T3 is, you can't imagine Skynet getting anywhere without human assistance to a much later point. They'll probably retcon T3 and have humans developing advanced cyborgs.
Something like that was almost the plot of T4. Far enough into production that you can still see some of them in the trailers and in a couple shots of the movie itself.
The only thing wrong with SCC was that the main story dragged, there were a lot of 'Terminator of the week' episodes.
Lena Headey played Sarah really well, watching John transition from teenage brat to the person who'd eventually lead the resistance felt natural, Summer Glau played an improbably good Terminator. The story was going somewhere interesting, with terminators splintering away from Skynet and looking to make peace with humans. It treated the first two films with respect while very much doing its own thing, which I don't think is something the following three films did at all.