I don't see the map changing much at all, other than Republicans improving in suburbia around the country (which would really help in the Great Lakes, Mountain West, and some Northeastern metros). Overall, margins just fall towards the middle and the country becomes less polarized, but no ground-breaking change in the map.
A "libertarian GOP" to me means they stop fighting gay marriage, tolerate marijuana legalization, change strategies on the War on Drugs, but remain pro-life (from the libertarian perspective that it violates the unborn's rights), remain very pro-gun, anti-affirmative action, and permissive on other issues but from a conservative standpoint. On economics, they generally stay the same, minus the corporatism-lite. And foreign policy would be slightly less interventionist, but still "strong on defense".
I don't see the south voting Democratic outside of NC, Virginia, Florida, and Georgia, because they are just so culturally conservative and now tow the line on GOP economics. Just because the GOP becomes more permissive on social issues, doesn't mean cultural conservatives are going to go vote for the very liberal Democratic Party. The voters who voted for Bill Clinton and Democrats like him are all dead now. Baby Boomers, being heavily Republican, still dominate the electorate and will do so until Gen X and the Millenials start overcoming them, which will take decades, and that's why I'm confused by people who say Hillary can win Arkansas and Democrats
suddenly start winning the South. Where will these votes come from?