People think of early reflections only from the side walls, typically ...which doesnt complete the picture at all. You've got early reflections from the floor, ceiling , back wall etc.. these can all affect the sound stage.
Installing a thick(shoot for 100% pure wool..not the synthetic hard variety) rug between the speakers & listening position, made a night & day difference in my 2 ch music listening in office room with hardwood floor. My left ear was taking the blunt of the reflections..and this is not just ear fatigue. No more!
It will not have a big impact on the lower frequencies(bass) , but Mikdado is right, room can become overly bright and the high frequencies get bounced around, without a large area rug....