From everything I've read and per my interpretation of it ... A small room will produce more standing waves than a larger room (all dimensional ratios equal), which leads to peaks and valleys of sound in the bass region (up to about 300 Hz give or take). The character of the standing waves depends on the room dimensions. From this perspective, the room size has more affect than the placement of the speakers. The speaker placement does have a strong effect on how and when the music reaches your ears from a reflection perspective. This affects perceived soundstage and varies by speaker design and surface treatments in your room. You seem to have a very reasonable and appropriate setup. If you want to experiment, I'd suggest moving the speakers around a bit (one foot here, two feet there) and toeing them in, flat and out to hear what happens. Don't rearrange the whole room just yet.
My best loved musical experience has been in a small room with handbuilt cabinets, professional JBL speakers, McIntosh amp, Crown preamp and turntable. We were nowhere near ideal positional ratios (the proverbial equalateral triangle) and it sounded great. The cheapest tweak possible is simply moving the speakers around. Try it ... you might like it. Happy listening.