While there are moderate center-righties in New England who have been voting Democrat because the Republicans have gone of the deep end, saying that bringing them back presupposes that there are THAT many of them that they could turn these huge New England Democratic margins into Republican victories, which is ridiculous.
If the GOP would go back to the party of HW and Dole, they could turn NH into a real swing state, ME into a lean D state, and guide MA and CT over to the right a little bit. However, one of the main reasons these moderate GOPers are voting D now is because NE is overall a very liberal area, and their progressive tradition is enough to make it so that the only way it can go red is for the GOP to be the liberal party.
Which makes this debate moot.
Again, you start with the premise (which is nothing more than wishful thinking and revisionist history) that the GOP has EVER been a "liberal" party.