Somewhat similar situation with a a fairly narrow, asymmetrical room. For me it took finding the right speakers that worked the best within my limitations. Martin Logan ESL's were the answer. Because of their narrow horizontal dispersion and line array type design, they eliminated most of the reflection issues I was having and took a lot of the room out of the equation.
I realize switching speakers is not an easy, simple solution, so my suggestion is to play around with placement and add some room treatments, if possible. Balance issues can often be mitigated by a combination of absorption and diffusion.