Thinking out loud:
We only have the numbers that the game returns: Kills, Captured Enemies, Lost, taken by the enemy. To leave out one of the numbers (Prisoners taken or lost) would not be right. I think we should stay with the count that Polar's reader gives. Meaning Prisoners count as kills. Iirc the Samurai didn't really take Prisoners anyway and in Shogun you only have "heads taken".
Now, whether you pursue those routing troops to make more kills is your decision, as Masamune points out it may weaken your army and you may miss crucial units which are at the edge of the map.
I think the number of kills is a nice indicator but it only tells you so much about the players performance. As Masa pointed out, you may be crucial for the team victory but may have a low number of kills. In that case all participants will know and respect that. I don't think that the participants of this competition will dwell on their number of kills and taunt others. (Well maybe they will )

The previous rounds of Samurai Warlords have always taken place in a very relaxed atmosphere. Although we add this competition layer to our gaming I don't expect anyone to take it overly serious in a way that would change our gettogether.


R'as