This is great for people who don't like the way they built their houses, who they adopted, who they hired as their stewards or are encountering any bugs regarding those. (Not going to fix freezing problems or anything like that)
My wife was bugged when I asked her to move to Windstad when I adopted children and she glitched back to Whiterun and wouldn't move anywhere as if we were never married. So I uninstalled Hearthfire, loaded my save and talked to my wife. Finally she would move again, so I moved her back to Proudshire Manor and made a NEW save. Then redownload Hearthfire and loaded that new save and I was able to speak with the Jarl's and buy the land again and also adopt new children.
Hope this helped anyone who wanted to restart. Lemme know if it worked for you.
Note that the downside to this is you don't get all the gold back that you spent on building your houses and furnishing them.
Also any gear you have you will want to take out of the house or it will disappear.