Our door won't close, is it a sagging door or a misplaced strike plate?
How old is the house? If a newer home, uneven shrinkage in the floor framing may be the culprit. It seem rather than rehanging the door it may be best just to grind the hole in the strike lower rather than having a notch show where the strike is lowered. If you  don't like the gap at the top, then resetting the jamb is the way to go, other than raising the door on the hinges and trimming the top.