The shower looks too close to the bed IMO. If you don't put the right ventilation in your whole bedroom could get humid (leading to dampness).
Adding a window to the WIR (see Tribe7's post) is a great idea to get natural light into the space. If you're good on the tools you could then make a swinging hindged mirror (A: to use as a mirror, B: to block off the sunlight when needed). When you use the mirror its blocks the window... and when you're done you open it and the light comes in.
Keep at it!!!