Do you want this to be a big reno? meaning, will you replace things totally or do you want to work with what you have mostly? will you add a toilet to the bathroom? if you replace the vanity, you can put in a larger one curving around the corner with a medicine cabinet above. If you replace the shower with one flat on the ground, you can also put in clear doors for bigger visual space. how about re-painting as well

As you rethink adding a fixed window, consider either a fixed window that is the long horizontal kind over the shower/tub surround and/or an octagon one with stained glass for the dressing room. https://www.google.com/search?q=images+for++octagon+windows&biw=1366&bih=673&tbm=isch&tbo=u&source=univ&sa=X&ved=0CCIQsARqFQoTCOaJ69fb28gCFcYVPgodogsLDw You could add a couple of pairs of shutters to create a pair of faux windows that look as if the shutters are closed. If you don't want a window that opens on that wall, you might consider having a fixed window and shutters that are louvered to let in some light while protecting your privacy. You might also consider a faux gable with a faux window, perhaps functional as part of the venting system for the bath.

The all black kitchen looks scary as. Maybe because there's no lightness in there at all.

I think the most impact would come from a well placed, well sized Acer. You can get them grown fairly tall already, Tamata have them and I'm sure there are other places. I'd get one that grows to no more than 3 metres (although check this against your property as scale is hard to gauge from photo), and has changing colours of leaves/bark. I'd place it towards the left of the property, looking at it. That will give some balance to the windows, provide some privacy but not obscure light. It wouldn't be a cheap option but cheaper than painting the house, and would need almost no aftercare. Then some easy care phormiums in the border underneath the windows. Both phormiums and acers come in a range of colours- limes, bronze, purples, oranges, dark reds etc, so choose what you like. The acers are soft and provide movement and variety, the phormiums sharp and provide solid consistent structure. This echoes the plants that can be seen already behind and at the side of the house and should make the hour 'sit within' its environment instead of bing perched on top of it. Also, the edge of the driveway- I would dig a border to just beyond the seam of the gate, lay down a weed mat, and put some stones in there. The garden centre has a range of them, in several colours from white through green red greys and blacks. If you chose reddish (or reddish and lime/orange) tones for your acer/phormiums, I would prob buy a large specimen plant in a pot for the top of the driveway, at the eight hand side of the garage, to link the colours. And maybe paint the front door and have some pot plants there that tone in too, especially in the area near the path that can be seen from the street. For a cleaner line I'd consider painting the lower part of the decking (the vertical frontage) to tone in with your house.