We prefer to elect tribal elders for POTUS. We predominantly elect them to Governorships, the Senate, and the House as well. There are set paths to becoming an Elder, whether a thane like John McCain, or a counselor like Biden. Even our younger candidates are less outsiders than Young Turks, the rising generation pushing the old guard away before they were quite ready. But even the Young Turks are generally drawn from that pool of young people being groomed for leadership. They might come from an opposition party, with less hope of predictable advancement than the sons and daughters of those in power, but they are still recognizable in form.
Obama is a Young Turk, but clearly from the standard pool of Ivy League, up through the political ranks elders-in-training. There are business pools and military pools training elders as well. Though Bush positioned himself as a contrast to this group, he only differed from them in part. Gore, Kerry, Bush 41, Cheney, Quayle, Dole, Mondale - all these were standard elders. The Clintons were a special case but like Bush, not very unusual in the end. Bill was rather a colonial from Arkansas, educated back in the mother country of Ivy, then sent back out to evangelise his home country with the aid of Hillary, a nearly archetypal tribal elder.
For although it was, and is, a predominantly male eldership it was never exclusively so, and certainly less so now. Eleanor Roosevelt was a tribal elder in a way that Mamie Eisenhower was not. Most female Senators and Governors are from this mold: Elizabeth Dole, Susan Collins, Jennifer Granholm*...Olympia Snowe is a mildly exotic version of the same. A few women in the House escape this mold. Nor is it especially racial. Condi Rice, Colin Powell, and Jesse Jackson are tribal elders. Al Sharpton isn't.
You know where this is going. Sarah Palin is not a tribal elder sort, and that scares the stuffing out of people at some primitive level. She certainly could morph into that role over time, as Ronald Reagan and Jimmy Carter gradually did. Both of those presidents started elsewhere and had some success before turning to politics. Both had something of the nonstandard about them, but both ultimately settled into tribal elder status.
News anchors and journalists clearly see themselves as tribal elders. They hate the alternative media not because those are Young Turks angling for their positions, but because they want to overturn the tribal elder system altogether (so far).
Palin is not without precedent, however. Ross Perot was never a tribal elder and never became one. Had he been longer in politics he might have become one; the role seems to bend the man. A few candidates come along in each primary - we don't choose them. Jerry Brown and Ralph Nader are tweeners, having moved off early to worship Loki instead of Thor and Freya. To succeed from outside the pool of elders you usually have to be some sort of fusion in your earlier career - the military/entertainment Jesse Ventura or the entertainment/business Arnold Schwarzennegger.
Obama makes much of not looking like the other people on the dollar bills (yeah, like Washington and Franklin would just blend in so well now, y'know?). Palin would not only trump him badly on that score (as would Hillary), she upends the system at a deeper level as well. Whether she goes on to become Vice President or goes back to being Alaska's Governor, she will (likely) slowly take on tribal elder characteristics, as Margaret Thatcher and Golda Meir did. But she could still stand apart from that archetype even as she keeps roles that supports it.
*Did you know that Jennifer Granholm was a beauty pageant winner? Shouldn't that disqualify her from being a Democratic, feminist governor?