It very much depends on the height of your living room sofa. I remembered purchasing my very first lcd and when the deliveryman arrived, they asked me to seat down comfortably on the chair and they will either raise or lower down the lcd to suit my viewing pleasure.

And to TS. As mentioned, you can either hack those wall to conceal those wire. If you do not prefer hacking, my another solution would be custom made a wooden panal as a decorative panel to hide those cables. That is what I do for my living room and family hall. Result is satisfying.

I believe you can always spray or paint them to your desired color. Not a big deal here.