First, it’s unnecessary to win. The most well-tested electoral strategy for a Democrat would be to simply reassemble the Obama coalition of young people, white college-educated liberals, and minorities that delivered the presidency in 2008 and 2012. Indeed, as Jamelle Bouie points out, that coalition has only grown over the last four years — and given Trump’s staggering unpopularity among all those groups, it should be fairly easy to reassemble. Latinos in particular are chomping at the bit to vote against Trump; his deranged anti-immigrant xenophobia is sparking mass registration drives all over the country.
Second, Clinton should be more worried about her left flank. She has generally won minority populations, especially African-Americans, but Sanders has dominated among young people, and she needs those voters. This primary has had big ideological and policy differences, and while Democrats generally like Clinton, she clearly isn’t the first choice of a big fraction of the party. Any sop to conservatives would risk bleeding left-wing voters who are already suspicious of her fairly conservative domestic record and hawkish foreign policy.
It would also, you know, be morally wrong to advance bad conservative ideas if it can possibly be avoided. Neocon elites are probably the likeliest faction to defect to Clinton, and what they’d want is blood-curdling aggressiveness overseas and Benjamin Netanyahu in charge of Middle East policy. That would be bad.