You actually have a great opportunity! Make the window wall ground your bulky headboard by adding panels wall to wall behind the headboard and side tables. Mount them at the ceiling and you can completely make the window disappear if you want to. OR if you prefer to have the breeze blow on you during your sleeping time and need to be able to open the window, then part them in the center for accessability... but then I would paint the wall what ever the background color of the fabric that you select.
This is an easy and fun fix!

I have to agree with Interior Changes. Dress up the window with lovely drapes and make the whole wall a focal point. It will be lovely.

HI -- Dress the whole wall with drapes . Paint the trim around the window the same color as the wall . Find some bigger matching bedside lamps . You could use a semi-sheer drape or have sheers under the drapes. But fill that wall - floor to ceiling and side to side , Find some nice bedding ,- it will make the room !

I have a similar bedroom with a kingsize platform bed that my husband and I built ourselves and we needed ideas for that wall. Thanks for the insight!

In addition to the suggestions above, just changing the blinds to coordinate with the bed would look good. More cohesive.

This is also a great idea: http://www.apartmenttherapy.com/ways-to-fake-a-canopy-bed-168372

Thanks to all for the ideas. I think just a solid drape covering the entire wall would work. I feel like I can't do too much though because the headboard and four posters are so busy.