Not sure about your dislike,but from what you generally state: I would leave fireplace as is/don't install the arched passage walls. Instead, if you must,[but I would wait on any construction],extend the wall behind oven to the left or up in your sketch.Remove the central worktable or island or whatever that rectangular structure is in the kitchen. Because of the longer wall behind the oven and cleared floorspace,you'll have a bigger U shaped kitchen. Then-up where it says BREAKFAST, do a seating arrangement around large island/or table... search out your perfect"look" for that spot. On the other side of stairs,where you crossed off closet and made X marks, set up a dining spot with chandelier/better table/chairs with extension capability[or drop leaf]. Remember-you extended the wall in kitchen so you have enuf of a break from the busy activity in kitchen to make this a dressier area when you want,and when not using it, it's set out of the way. The furniture placement, with this dining setup positioned off to the side, behind chairs or sectional which face outward toward fireplace and island in the left corner area, is easy and no expense/construction involved.If you construct walls and arches right now,your options decrease-I wouldn't do that, and moving the fireplace doesn't accomplish anything really.