I'm not sure. But I'm thinking there are two explanations. One is that she is a dottering old woman, in which case that will be clear in the hearings and she will be gone.
The other is that, having spent the last years of her life vetting candidates and preparing them for questioning by the senate, she has a keen sense of what to say to the democrats when they ask her questions. And the "correct" answer to this question for her was really Warren Burger.
I'd love to hear her explain WHY that was her answer. And maybe her explanation would scare me.
Considering the gnashing of teeth her nomination has caused on the right (the left has been keeping its lips shut mostly) it had to be the height of foolishness for her to suggest, to anyone, someone like Warren Burger as her favorite justice. If she was worried about offending Democrats, she could have picked Rehnquist, who lacks the scare value of Scalia and Thomas, and is also still enjoying the glow of approval that always follows someone's death.
Honest or dishonest, it doesn't speak well for her.