The problem Palin's facing now, is the same problem as when she quit the job of governor. It's a maturity issue. We expect and need leaders who are professional, mature, and can handle pressure. Writing on your hand doesn't "bring you down to earth", it just makes you appear very immature. If she would have at least had a 3X5 index card, it would have been much better and come across as much more professional.
It's not a big deal she wrote on her hand, it just doesn't come off well for someone who is still considering a leadership position in the country - though realistically, I don't think she's a viable candidate.