'bout a few weeks ago, someone posted a node network that will allow poser lights to obey inverse square. Haven't tried it yet. GI may add realism to a scene; most GI solutions are slow and not (animation) production friendly. I believe it's possible to achieve a similar look with well thought out lighting, except extreme cases such as caustics. Other than what has been previously mentioned, tuning specularity / specularity maps will go a long way towards giving materials a more convincing quality.