My bet is that the coffee table between the speaker and listening position is a major problem area. If it cannot be moved elsewhere, I would at least put things on the table to diffuse the reflection, such as magazines, art objects, some kind of cloth covering, etc.
As far as room treatment, most of the serious audio treatments are pretty ugly and intrusive. Wall coverings (tapestries) on large, flat surfaces do a really good job with higher frequencies and can actually look good too. Some people also used potted plants in corners of the room to act as diffusers (I personally have not tried this, I use stacks of 16" ASC tube traps).
I would certainly hold off on trying alternative speakers/gear. Your speakers should be good at imaging, and if they are not, the problem most likely lies elsewhere. I would concentrate on trying different placement and geometry (toe-in, angle between the speakers and the listener, backwards tilt, etc.).