I mostly agree and you may be more quick witted than I am, but I thought that was a real think on her feet moment for Clinton. I thought about the question before I heard Clinton's answer and nothing I came up with remotely as effective as what Clinton said and I still haven't come up with anything more effective. Of course, like you said that would have been her answer was regardless of the probabilities of an indictment.
Perhaps the Clinton bashers* in this thread could take a break for a moment and give Clinton some profs on her quick wit there. My guess is they can't or won't. Once you're deeply invested in the Clinton is the devil meme, it's hard to pull back even for a moment.
On a different subject: One of the things I have been curious about since the beginning of this scandal is why the heck she did it. It was deeply hypocritical given her earlier castigation of the Republicans for doing essentially the same thing and it flaunted the rules in a couple of significant ways for great risk and very little to gain. I doubted that it was to cover up some nefarious communications because I doubt she would be having those via emails, because high level corruption often does not include explicit quid pro quos and I thought there was a reasonable chance she wasn't engaged in criminal shenanigans with respect to her foundation.
So why did she do it? I believe the answer was that she liked her blackberry, she wanted to keep using it and the NSA told her she couldn't have a secure one. So she just thought she'd be cute and have her own server set up so she could use whatever devices she felt like. It seems a bit ludicrous to take the chances she did for so little gain, but we've all made stupid decisions in our lives and this just happened to be one of hers. I'm a bit concerned that he management style creates an environment where she surrounds herself with sycophants that don't challenge her, but for me, she's the best choice available this time around.
On the other hand some of the other candidates do offer even more opportunities for humor:
http://www.truthdig.com/cartoon/item/trump_the_laughingstock_20151228
* please feel free to substitute your own noun if you object to this characterization.