Not to be a sarcastic person, just meaning you have a big job ahead of you and a messy one at that.
Could you not paint the brick a color or stain that would be more pleasing to you? Could you not accesorize it to a more pleasing style?
painting of fireplaces is a trend now and being a trend, its for life. Removal is quite difficult and to do it right, you need a small portable sand blaster. One with the capabilities to build a tent in the area and to contain all the debris.