I think we need a bit more info about your style is it traditional with that table or are you open to fun suggestions . Is the niche included it the size iof the space. IMO a 72” round table will fit , a bit tighter than I would like but okay because of the opening to the left. You might be able to put a nice buffet in the niche to save some space I think it could be qite nice with a round table.I am a bit confused since in the floor plan across from the niche is a bank of windows . Are you planning on removing those because if so that affects hoe the space is used and that table might not work if that space become a walkway to a porch. Maybe a bit more info BTW a 72” table can easily seat 8 people all the time

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Maybe consider a round table that expands to an oval to accommodate a larger grouping.

I would also suggest your room requires a larger chandelier.