I don't beleive that dedicated lines are the key to your short comings although may be a part of it. IMO, you already told us the short comings, placementand the room. Being in the same boat as you, in a family room with little flexibility, I am content with my current setup. When I get a dedicated room I will become more critical.
What is disappointing about the bass? Lack of, sloppy...?
If possible, try some room treatments.
What is disappointing about the bass? Lack of, sloppy...?
If possible, try some room treatments.