Anything done by executive action can be undone by executive action. If republicans can prevent legislation ratifying Obama’s actions and can stop fighting one another long enough to elect a president committed to the rule of law, the country can be saved.
As for executive actions, yes, the next president can undo them. But the precedents have been established, that the executive can make law, which de facto repeals Article I Section 1 that lauched the American republic.
It is comfortable, yet silly to think that elections alone can cure what ails our country.