Much depends on your budget for this project. Yes, painting is for ever, but it does create a new look and a bright clean one too. I do much fireplace painting in my business. You can dramatically enhance a massive obtrusive brick wall into a thing of beauty to suit your desires.
But, the next homeowner may not like this and it could deter from your market value. And it is permanent.
Tile resurfacing would also work for you, but its expensive and is very hard to remove to get back to the original state.
Consider leaving it and accessorizing it with brass or antique brass accessories. Many interior dec's are very experienced in this area.
Sconces, fireplace tools, fireplace opening, nice mantle, nice picture, track lights, and all that will make it look nicer immediately.