Originally Posted by divan
Zola didn't look like someone who takes the initiative. If the Winter Soldier is indeed his work, it's probably because someone else (either HYDRA remnants or the Soviets) ordered him to do it.
Granted, WWII-era Zola looked like just a flunky for Red Skull. But a lot happens to him by the end of that movie, and undoubtedly, a lot happens to him in the years leading up to present day. He's probably got motivation now to change.
The way I look at it is that Arnim Zola was a mad genius before WWII, and Red Skull bullied him into being his *****. Zola dutifully mass-produced a whole arsenal of extremely advanced weaponry for him until his capture by the SSR. Now that Skull is gone, and assuming Zola escapes/defects or whatever from the US, he's now free to be the mad scientist he always wanted to be.