We also have to remember that the quality of a particular move should not be
seen in isolation, a player might try a risky (losing?) move to avoid a
clearcut draw because he needs the full point for his tournament result, or
maybe he just dislikes draws.
If for arguments sake, he does this on a regular basis with 60% result, his
ELO should benefit, but a move based rating system will punish him. (I think
that to a small extent Tal played a bit like this).
The trick of chess is, pose problems that your OPPONENT can't solve. You CAN
play speculative moves when he's in time trouble. As Simon Webb said in his
excellent little book Chess for Tigers, play the man, not the board. We play
agains human beings who have likes and dislikes, become tired and irritated,
and only the game result counts, not how you got there.
An interesting idea however, is a "unified pool". Surely we cannot be that
far away from being able to rate all games out of the same pool for
consistency?

Joe