I agree the brick looks a little dated and dark, although the mantel looks small or to narrow for the large wall behind it. A paint color in that room and then maybe a whitewash on the brick would liven up the brick. Some accessories around the fireplace would give it some life!

I like it, What is white on either side of the fireplace, paint it a dark color from nature. I am going to suggest this green. This is B.M. Urban Nature.

Or take what is over the doorway and hang it over the mantel

I agree the mantel looks thin for the wall size. It does not look dated though. Hard to tell from picture, but if it is shiny, that can date the look. If you restain it to a flatter finish, it might help.

A thicker mantel would make a world of difference. I also incorporated JudyG's suggestions here because I thought they were interesting.

Do you use the mantel? You know where I am going with this...I think I would get rid of the mantel all together and white wash the current brick. You might also consider blending and extending the brick higher up the chimney.

Are you staging for resale or are you seeking suggestions for yourself? The art over the doorway looks industrial -hard to tell. If so, then the brick is fine as is. However, if you seek a light coastal vibe, then the brick must go.