Dick Cheney was
absurdly unpopular in 2008, like low teens approval rating. And Romney as his running mate would hurt him even more after the financial crisis. This is indeed the worst possible GOP ticket for 2008, aside from maybe Dubya himself as Cheney’s running mate. This might if anything be generous to Cheney; not impossible to see Alaska, Alabama, Mississippi, Kansas, and Nebraska falling too. And if anything I think the flipped Democratic ticket might actually be even stronger; Biden would have more appeal to WWC-dominated states at that time like WV and AR, while Obama’s presence on the ticket would still turn out black voters in droves to help in states like SC and GA. Hillary at the top of the ticket might have done even better that year.
Regardless, absolute devastation for the GOP. Polarization aside, worst blowout since 1984. Definitely in the popular vote (Cheney gets trounced by double digits) and very likely in the electoral vote as well.