My sink and window set-up are very similar to yours, right down to the window moulding abutting the sides of the cabinets. the only difference is that our sill is much deeper. We have a tall faucet as well. If you're thinking that you need to tile the sill because it will get wet, I can tell you that our sill does not get wet. Don't know why, but it just doesn't. If you want to, you could trim or remove the part of the old sill that sticks out horizontally and use a different piece of painted wood trim applied on its side. By this I mean so its front is flush with the front edge of the moulding on the side of the windows. This is what we did. We have a piece of moulding about 2 inches high and maybe 5/8 inches thick. The side window moulding runs into it. So it's like a frame to the window, but a different profile from the side moulding. It looks like it belongs there. We needed a flat moulding to have room for our faucet. We tiled up to the bottom of the cabinets, and the tile runs into (and stops at) the moulding on the sides and bottom of the window. It looks nice. Sorry I haven't learned how to post pics.

Do these photos make it more clear? I've added three more things two of which currently don't exist. Label: Addition - this started out as location for downstairs powder room + laundry + would house 5ft wide coat and shoe closet. Now, considering making it a quiet area, sitting space, piano spot, place for coat closet? would probably have it open to the foyer or glass doors if needed. Label: Possible spot for 1st floor powder room. Self explanatory. Deck - This exists and the spot for powder room is eating in to the deck area as it is currently. NOTE: I've added more detail to the photos in the first comment

No Sophie, things are the way they are because they needed to be done. The work being done was/is needed regardless of what happens with the kitchen/dining. Now however is definitely design phase be it architect or kitchen designer or both. We're limited due to cost of things and of course the cost the actual construction itself.

Although there would be some wasted space, you might consider putting the cooktop in the corner. That would allow you move the ovens over beside the fridge. In turn the sink and DW would need to move toward the door. In the larger drawing I enlarged the window, but if that is not possible due to the brick veneer, you could move the sink off-center to the window, but set the faucet off-center to the sink--more centered on the window to disguise the off-center sink. I eliminated the stub wall beside the fridge to provide more space between the ovens and hood. The fridge would then have a wood surround with a full depth cabinet above. Have you considered a MW in the oven stack? Images--corner cooktop