Eminent domain is bad because it favors corporations with lots of money and ability to defend themselves in court over your everyday citizens who probably don't have the money and the resources to defend themselves against a rich company. It isn't right that someone can forcably buy someone out of their land and the home that they love.
Eminent domain is sometimes necessary but the government has been overstepping its bounds and infringing on the rights of citizens. It should only be used when a public use such as a road is in play. It should not be used if another private company wants the property to enhance the property value.
Usually the private sector does not get much sympathy from me.However, the private land owners like farms or just personal property are a different story. The Keystone Pipeline is a perfect example. The ranchers and farmers who own land in Nebraska just stopped the Keystone Pipeline from being built on their land, because they do not want the pipe to leak and poison their water supply. To bad it is not over yet for them. The government can still use "eminent domain," in order to build the pipeline.
The national government rules over all the land. It is entitled to use this land in any way it deems fit. People that believe the land they purchased is their little plot of planet earth are misguided. The only way to own your little piece of earth is to create a sovereign nation. Even then the political and lawyer garble behind the legality of you and your little country still does not assign the land to you. It assigns the land to the people of Mylandia, even if you are the only person there, it still does not belong to you.
No, I do not think that this policy is all that bad. It has been around for a very long pain, and if it was a very bad thing it would have been gotten rid of a long time ago. So I think it is a good thing to have.