Shrillary may be a worse candidate than Kerry, but that remains to be seen. (I like what you said about her voice -- "like a car alarm" -- good one!) Kerry was indeed pretty bad, and he came very close to winning, against a Bush who was more popular than now, and with the Iraq war more popular than now. I tend to agree with Dick Morris that there will be a massive turnout of single women (normally not very good voters) for her. The media bias will be at least as bad as it was in '04, and I suspect worse. For two reasons: One, feminism. Two, if Newt is the candidate, an awareness that the MSM and Rats are faced with a much more serious opponent (should Newt be elected) than GWB was. There has been only one elections in which there was such a direct threat to this Establishment: 1980 with Reagan, a situation that tilted our way because there was a Democratic administration to blame for the economy and the international mess. In '08, incumbency will work against us, even against Newt if he's the nominee, even though Newt is, in substantive terms, practically the anti-GWB in terms of conservative seriousness.
Morris is also underestimating how much she'll suppress the male Democratic vote. I work with two hard-core Democrats, they both swear they'll stay home if she gets the nomination. They may or may not, but she's the only candidate in the field who evokes such an instantaneous, negative reaction. I think any gains she makes with single females, she loses right back with blue-collar male Democrats.
Your point about the incumbency working against is well taken. But Gingrich would have one advantage: he didn't vote for the war. Whether or not he would have is irrelevant. Hillary's going to have a difficult time playing guilty-by-association with a 10-year private citizen over a war she authorized. If the War Blame card is off the table, all we're left with is ideas. Obviously, that plays to Newt's strength.