None of you paid attention to the movie did you - the ONLY surviving Autobots were the ones that appeared in Age Of Extinction. Sideswipe is not returning and neither will any of the remaining Wreckers or Jolt. Brains is alive and while I don't completely discredit the idea of Harold Attinger lying to people its much more likely that is was of Que - regardless we know the state of both these robots.
The hell is wrong with you, Scorps? All because they didn't show in AOE doesn't mean they're dead. Did they show Swipes and others get killed? No. We're lead to believe most were hunted down and killed for Transformium. And Swipe's card did NOT have an X on it. So.... yeah.
One might rather believe that Sideswipe and the others were hunted by Lock-down alone with no acknowledgement from Cemetery Wind since the two haven't met yet. I recall dialogue mentioning they're all that's left. Brains doesn't count to them in theory.
The only thing I've seen remotely close yo being helpful is this, which was debunked, but fairly accurate
Didn't Drift or Chairs say they took everyone else out? One of them said something along the lines of all other bots being hunted down already, and they were it.
I could see Sideswipe leaving after Chicago Due to his Mentor being killed, no one really ever discussed that...just an theory But I'm real fed up that we didn't get a real explanation in depth... guess only time will tell.