After scanning the reactions of over at TOS, this pick would have the potential to make the election the ultimate win-win-win result:
1) Clintons lose
2) Schadenfreude from watching Clinton supporters cry
3) Schadenfreude from watching some Trump true believers cry at being "betrayed" with the appointment of "Willard".
That's really about as good as it gets as far as I'm concerned. And, I actually like the idea of Romney as SoS, so that's another positive.