We thought any more than one song/album was going to get a bit outrageous for actually listening to the playlist.
I'm not wild about more than one song per artist, but your system seems great.
It could easily turn into a greatest hits playlist for The Beatles, Stones, Floyd, and Zeppelin type bands, so I get the concern. I am open to other suggestions, or maybe we just try to encourage some deeper cuts from some if the albums we know will be on there.
MAYBE the person with the highest score has the option to replace it with a song/album that didn't make the countdown somehow? Maybe their highest ranking album that didn't make the cut. For eample, i ranked Dark Side the highest i could take a song off that or my #2 album that i know will not make the countdown.