50%    McCain
45%    Obama
6%    Undecided

First, I'd suggest that he be very careful not to make remarks that can be construed (through sound bites or out of context citation, etc.) as positive about the conservative movement, Reagan, or the Bush administration.  Most of the remarks that have generated the churn have been ones made when he's speaking to conservative media but honestly, I don't think he needs to make his case to Republican crossovers and indies in that way.  His anti-war stance and his desire to rise about partisan bickering is enough to attract those voters while not pissing off core Dems too much.  He has to make his remarks more bulletproof.  

The second part of this is a little tougher given that he's running against a Clinton but I think he has to be very careful about the remarks he makes about Bill Clinton and his legacy.  For many of us, those eight years (despite their problems, challenges, and in some cases, failures) are the only bright spot in our adult political lives.  Reagan-Bush I-Bush II have been a disaster for the country on many levels.  I doubt the small core of Bush II supporters who remain will vote for Obama anyway, so run against Bush, not Bill Clinton. Take a page out of the Republican playback and honor folks who should be our Democratic heroes.  Feeding the Clinton hate only generates a backlash that he can't afford.  I realize this is tough thing to ask because since the economy has become the hot issue, Clinton benefits tremendously from good feelings about the state of the economy under a Bill Clinton administration.  But there's a lot of clever political tacticians out there and I have to believe they can find a way.

Third, I think it would help him with women if he came out hard & very vocally against the misogyny directed towards Clinton in the media.  He wants to cast himself as part of the solution not part of the problem.

Fourth (and this relates to #3 above) regardless of who started it and who said what, he needs to have a zero tolerance policy for anyone playing the race card (I hate that phrase but I needed some shorthand to refer to the issue).  Things are starting to get very sharply divided along demographic lines and I think he needs to try to blunt that as possible because there are more Dem voters in categories that he's not strongly capturing.

Obama has a huge advantage because he's a tremendously inspirational speaker.  I've seen a lot of folks that I think of as more rationally than emotionally-oriented go totally ga ga over one of his speeches.  He can still push his core message of change and the power of the individual minus the behaviors above and it will still be effective.  Hey, I think he could deliver Hillary's campaign message but by virtue of his oratorical ability he'd beat her every time.

Like you, I suspect that, deep down, Obama shares Hillary's and Edwards' progressive values (though with the tone of his church talk I think he is inadvertently legitimizing a lot of Christianist bigotry that could cause serious damage to the country if he were President...not that he himself is a Christionist bigot, but he is certainly pandering to those who are...see that South Carolina flyer).

You have to run as the transcendent "high concept" unity and hope candidate.  Otherwise you wind up like Jesse Jackson.  
Whereas the Clintons are free to play the identity politics card against Obama to win.

That's just the truth.

Obama has brought out record-breaking numbers of new voters, winning some surprising demographics, and scoring support from independents, Republicans, and endorsements from Democrats in conservative states who know he will help Democrats all down the line, unlike Ms. Clinton.  Hillary...has two decades of name recognition, a nuclear-powered political machine, and a beloved former president campaigning for her.  The only place where there's any parity is in terms of cash.  The fact that Obama's done so well in spite of those advantages speaks to his draw and strength as a candidate.