Didn't Watch Dogs 2 flop? At least I don't think it sold that well. If AC isn't a key franchise Watch_Dogs is done.
I also don't think we'll ever see a new Just Cause or Evil Within.
Volition probably has to make Saint's Row V if they want to stay around at this point.
Ubisoft's sales expectations for AC are pretty low, relatively speaking. At their E3 it was "just another game" on their lineup. Their games lately have been successes though, especially Ghost Recon, so I'm wondering what else Guillemot has cooking. Their shares almost doubled in value over the last year too.
The Division is also getting new content all the time so I'd expect a very ambitious sequel to be on its way.