I think we're going to find after the Release of T4 (unless Summer Glau makes a cameo) that TSCC isn't long for this world. Lets face it, its a show produced by an industry that thinks we're too stupid to tell the difference between a Tv Superman and a Movie Superman, and thus "No Flights, No Tights!". So therefore the idea of two Timelines seperate from each other, but each a part of the same story, would make most people's mind blow up.
Hell, I had to explain that TSCC was set between T2 and T3, that Sarah Connor would get Cancer and die, and John Connor would end up living Off the Grid
by the series end before my Aunt would sit down and watch a single episode.
But that being said, I have liked BAG on this show, and I would be sorry to see him go.