Kaine did everything that Hillary couldn't. Hillary can't be aggressive. Hillary can't call out Trump as much as Kaine did.
Kaine wanted to pin Pence with everything that is Trump. He had to break some eggs to do so. I believe this is what Hillary wanted Kaine to do. To not give Pence a break at all and make him acknowledge Trump. And when Pence hesitates or argue that Trump did not do something that can easily be fact checked it makes Pence look uninformed on his candidate and it brings attention to the crazy things Trump have said.
Granted Trump hanged himself but Hillary was also pretty aggressive in the last debate and has been making sure everyone knows about Trump's bullshit for a while now.