One possibility would be to swap the living room and the dining room. Since the current living room is larger than the current dining room you could still keep some comfortable seating (couch and upholstered chairs?) against the front wall for a keeping room/dining concept. Then your new dining areas (kitchen and dining room) and living areas (living and drawing room) would have good flow between them, which would work well both for family and entertaining. You could also add some builtin bookshelves in the drawing room or new living room to create a library area to add another fun element to the living areas. These bookshelves could be against the long walls in the drawing room, around the window with a window seat in the living room (former dining room), or built to create some separation in the open area between the drawing room and living room/stair area. Your plan seems to show some sort of builtin there, but I'm not sure what it is.

So for this to work, you need to go back through my question and make sure you have answered all of them the best you can. Is the electrical outlet for the counter space going to be right next to the switch, or is it that blurred spot that I see in the picture, . If your walls are Travertine marble, and there are not already electrical boxes in the exact location the lights go, we are going to have a hard time. If a 30" vanity goes in the corner, and you leave 5" on each side for the lights, that leaves a 20" mirror with one light jammed tight into the corner. So if we leave another inch on both sides, for clearance, that leaves 18" mirror. If you put a 3" frame around the mirror mirror, that only allows for 12" of actual mirror. I don't think that is enough mirror. Your bath is too narrow for a mirrored cabinet with built in lights unless it is recessed into th wall. The plumbing is probably in the way for that. Give me your thoughts on what I have just said, and then go back and answer all my questions. Then we can take it from there with a narrower down and focused search.

It's a bit hard to tell, it looks like some of the proportions are not correct. Given what you have drawn it looks like entering and exiting your shower is going to be awkward. I'm not certain that you'll be able to open the door all the way because of the placement of the tub and vanity. Here are a few suggestions: Ditch the corner tub, and use a rectangular one that is installed with the long end on the wall opposite the vanity and shower and install the toilet next to the tub. Slide the door to the right, and you'll be able to have a larger vanity and/or shower. If you can use a pocket door or something of the like you'll gain wall space like sandpat mentioned. I don't see any storage planned. Have you thought about where you'll keep towels, toiletries, etc-?

I agree with divadeva. More lights. If you can add pot lights do it. If they're already there add task lighting and up the wattage on the bulbs on the pot lights (replace with LED and you can make them brighter because the wattage on LED is lower for brighter light). If you have all of that add decorative lighting. If ventilation is an issue find a way to move the air around or add air filtration. Maybe the HVAC is deficient. Maybe you can add a HEPA filter instead of the standard one that comes with the unit. Call an HVAC specialist to see if there is a way to boost air flow in the room.