You didn't knowingly commit a sin. We were faced with a tossup between getting stabbed or 3rd degree burns. Only now do we know that the knife was rusty.
In retrospect, had Romney won, we'd have had 8 years of Bush Sr-like governance. We would have likely gotten two Souters instead of Gorsuch and Kavanaugh. Then in 2020, we'd likely get President Warren.
All-in-all, the 4 extra years of Obama MAY have been worth it. The Lord works in mysterious ways.
I strongly doubt that scenario. Mitt Romney invoked no enthusiasm in the Republican Party and most Republicans felt that he was at best the lesser of two evils. Had he won in 2012, he would have been a one-termer. With his incompetence (as evidenced by his governorship) and his nature liberalism, his support in the Republican Party would have been weak. Hillary would have crushed Romney in 2016. All those fantasy landslide scenarios that Rachel Maddow swooned over would have come true for Hillary.