The trailer for Terminator: Genisys (why) is interesting, but perhaps not for the reasons they’d intended it to be. The film series has certainly not had much care for its increasingly convoluted timeline’s continuity after you get past the first two; indeed, this is arguably the second time in a row that they’ve attempted to hit the soft reset button on it (not including the inarguably superior TV interquel-cum-prequel-cum-sequel-cum-spinoff).
With that in mind, I can understand the desire to return to the simpler – and better written and directed – times of Terminator 2. And so it is with unintentional irony that the way Genisys (why) is presented just convolutes even further the mess we’ve been stuck with up until now. Hitting the reset button while simultaneously holding onto what came before can be done, but usually isn’t for these exact reasons. It’s like how Alexander “solved” the Gordian Knot by chopping it in half. One could argue that the knot’s now gone, but in practical terms you still don’t have a usable length of rope. Nobody wants the storytelling equivalent of hacked up frayed strands all over the floor. (Except in specific circumstances, I suppose.)
I like how Arnold’s ageing is explained, though. I’m glad they didn’t think of that during Terminator 3 and squander it there on a less-aged Arnold.