I like David's comments above and think that you should select a simple large (12x24") tile for your fireplace, light or dark.

What about mosaic tile? Lots of colors, styles, sizes, and finishes to choose from. You can also mix tiles or keep it simple and uniform - whatever you prefer! This fireplace was done in a single color of iridescent tiles, very sleek and modern! (other colors available!)

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.

Yes to all those ideas. I believe your cladding is unpainted concrete bricks (is it called Summerhill Stone?) in that (boring) fawn colour. My house is same but was painted by previous owners. It looks so much more up to date and the surface is lasting very well; no signs of peeling or flaking. So despite needing to maintain a painted surface, I think painting is the way to go. Alternative is a costly plaster job. Then the entrance - yes, wide generous steps onto a wide deck or patio, some vertical or horizontal slatted panels for protection or privacy as needed, clear roofing for protection and to allow light to the rooms. And paint the front door a vivid color to indicate the entrance. Just make this area feel generous! Dependent on the adjacent rooms and which direction the house faces opening up one or more of those windows into sliders or stackers would be great. Plants in big pots are good too, add colour and texture - and you already have some there. Good luck - I love the idea of turning an ugly duckling into a beautiful swan!