Your not far off, but you need to think of it as available space to work.  You wouldn't pan the basics of the drum kit: kick, clap, snare or bass.  Panning has to do with effect, stereo width, and depth perception.  If you have an effect coming in and its in the center it might sound ok, but if you started it on the left and ended on the right, it would give some movement to the track and it would begin to sound interesting.  Slightly panning percussion or synths in equal energy with opposite instruments or sounds, will give you a wider sound.  Generally music that sounds wider sounds better, as in real life sound travels in a wide perception in an uncompressed form, so you are used to hearing constant left and right panning, and depths in a wide stereo image.  Music should reflect some of that as well, and gives it some realness regardless of the genre.  Sonic space can equal a great recording, but its up to the mixer to create that.