I think that each kill should drop 1 trophy, after all you killed the Monster and should be rewarded for your efforts. After XP becomes 0 due to a high rating this becomes a lot more of a problem. If you wanted to adjust the XP given for the 5 trophy turn ins that would be welcomed as well, but we should be getting a trophy on the kills.
I realize that some mobs drop 1, some 2, some 0 and it's a ratio thing and if you hunt a mob long enough, you will get trophies, but It's a very weird equation. I can hunt and get drops on certain mobs, then all of a sudden it stops. I keep hunting them and then they drop again, it's like a timer almost, but the player is still putting forth the effort and should be getting 1 trophy. I am ok with some of them not dropping 2 or any of them for that matter, if I know that when I drop a monster I'm going to get one. It seems more fair.
-Kor