I think Hillary can very liberal for the most part in the debate. Sometimes the candidates will have to look centrists to gain any undecideds and independents. For Hillary's case she just needs to regain her support from other Democratsleaners and liberals. I doubt her main goal will be trying to gain other votes besides those groups because almost anything else is a lost cause. The current environment also is especially making it much easier for her to be liberal, mainly because of Donald Trump. When it comes to social issues she'll be very liberal, and most of her positions are actually popular nation-wide, or popular to a certain demographic she wants to have more support in.
National security and foreign policy, she'll won't be as liberal in, but that is probably for the best as many Americans aren't that much liberal when it comes to those subjects. It wouldn't be warmonger-y either though. Her positions will most likely be very detailed to the amount of time she is given and will look like it has some sense to it. Being a policy wonk will very much benefit her in this. I say in most subjects that they will talk about she'll should have the advantage, it just what her strategy is going to be.