If you have a crawl space or if its new construction we typically put in conduit from tv to remote location where all your electronics might sit in cabinet.

My husband and I disagree on this design, I want to remove this dated tv box, and he wants to go over the fireplace, and he doesn't want any component furniture. I think the hearth can be redesigned somewhat to hold two components. the sitting area is directly looking at the fireplace. My issue is that opening the archway is far more important.

If you can find a way to avoid having the TV above the fireplace - you will save yourself neck ache for a long time.
You want to remove the TV box - by all means please do. Could you consider a long low media cabinet to the right of the fireplace for the TV?

The only problem is it would be across from the kitchen, the family room is in this corner across from fireplace.