Let me posit something for sake of discussion - had Mitt Romney not been a Mormon he might have won, and it is possible that therefore Evangelicals within the Republican base will argue there is no reason for them to dial back on the social issue rhetoric.
Le's take the first. We have been told that the Evangelical participation in the electorate dropped 7%. Remember that something over 30% of Americans consider themselves Evangelicals. Further, some Evangelicals who voted down ballot for Republicans who matched them on issues wound up voting perhaps for one of the minor candidates.
Recognizing that Evangelicals are not evenly distributed across the country, I would like you to consider that Evangelical rejection of Romney because he was a Mormon could have cost him 4 states: FL (29), OH (20), VA (13), and CO (9). Assuming that FL will go to Obama, giving him 332 EVS, subtracting those 61 EVs would have resulted in Romney winning 277-261. While this proposition is arguable, which I acknowledge, I will not be surprised to find some Evangelicals beginning to make it.
And if they do, they will then proceed to argue that there was nothing wrong with their social agenda, at least at the Presidential level, the problem was the candidate carried religious baggage that made him unable to hold on to enough Evangelical voters to win the Presidency.
As the Republican party goes through the forthcoming soul-searching of how their party proceeds, if this assessment has any validity do not look for the Evangelical influence on the Republican party to diminish, but in fact it might increase.