There's a better than 50/50 chance that whoever wins the White House will get a divided Congress (Blue Senate, Red House). Not much will get done, but not much will get undone either.
Best Case: Democrat wins. Frankly, not much will get done in terms of new agenda items, but the ACA will remain untouched; Scalia will get replaced with no-worse-than-a-centrist; and the Democratic WH occupant will most likely get to replace Bader Ginsburg, Kennedy, and maybe Breyer.
Bad Case #1: Republican wins with a divided Congress. ACA does not get repealed, but may be modified. Most likely the SCOTUS remains conservative, but may get more so.
Worst Case: Republican wins with Red Congress. Senate exercises nuclear option. Hard-right replacement for Scalia; Planned Parenthood is defunded; ACA repealed. Senate and House most likely go Blue in 2018 midterm blowback. By then, much of the damage is done.
In all cases, no matter who wins from no matter which party, I see this as a one-term Presidency, and that may be the norm for a decade or two. My theory is based in-part on the mood of the country; changing demographics; and continued economic uncertainty. Climate change probably plays some role as well. We will continue to become less white; the baby boomers will continue to leave the workforce, and Alzheimer's /Memory Care expenses will soon rival college debt as an economic drag. We will continue to grow food in abundance, but much of it will leave to go to China. Weather will get less and less predictable. An increasing number of jobs worldwide will move to computers and robots, and we will have difficulties determining what is the way forward in terms of working and earning. This will be a time of instability and uncertainty, and Americans will continue to seek quick, simplistic answers and yearn for times that never really were.