"Starkiller is someone who could totally work in the Rebels continuity. The difficulty, though, is that he does these incredible Force feats. The way we conceived the game when we did it was that this was a Jedi tall-tale, like a legend. When Hayden Blackman pitched this to George... I believe David Collins was at this meeting when they set up this whole presentation for him. They did this video - it was all early concept and pre-rendered - of what a Jedi could do with Force powers. Instead of Force push just knocking someone over, it hit someone with like a cannonball, knocking them dozens of yards back. It took every Force power, and what they pitched to George, and amping it up to eleven. It was really doing an over-the-top game where the Force is just ridiclous. George's comment was, 'that is perfect for a game.' George approved it, but it is important to remember he approved it as a game concept... Force Unleashed was trying to pump up Force powers to a point we never seen before in the movies. If you take the story literally that all those things happened, it maybe breaks Star Wars because of the over-the-top Force powers. It wasn't just Starkiller's powers who were amped. All of the Jedi you face in the game - their powers are also amped, so everyone is up to a level eleven, which is why it is called The Force Unleashed. The thing is, the story itself was about a powerful Force-user, and the heart of the story - the events of the story - for the most part still fit into Canon."
This already sounds something he said before save the first line. That said compared to the other aspects with the EU it’s not over the top at all. That said I’d rather they not bring in Starkiller to Rebels.
__________________ "It didn't matter what they'd been before. All that mattered was that they were willing to fight—and maybe die—for the Alliance."―Col Serra.