First off, I oppose any eliminated/booted/surrendered players getting any points or any stat other than Loss.
In Diplomacy, you win not by eliminating everyone, but by owning HALF THE BOARD.
This very, very important rule changes *everything*, and is absolutely key to making it work. It creates some very volatile and clever balance of power which encourages exciting games.
(Notice that in my Player A-B-C example, Player A can win very easily, and thus wouldn't bother coordinating with either of the players. If they coordinate well together, however, they could have a pretty exciting and even battle with Player A, to earn themselves the right to be included in the draw.)
I don't play a lot of FFA, and the FFA I have played didn't have a lot of diplomacy, however, I think a Vote for Draw feature would capture some of the dynamics from the boardgame Diplomacy.
Your Player A-B-C example could demonstrate this. You are right to note that Player A could easily win, but if Players B & C coordinate, they might be able to stop him. But another situation now arises -- if player B plays his cards right, he could finesse a win for himself. Maybe he'll convince Player C to suicide himself into Player A while growing large enough so he can't be stopped (say on RoR Player C breaks Player A's Parthian Empire while Player B focuses on completing Spain/Carthigian/Africa).
But then Player A could point this out to Player C and get him to hesitate just enough so Player A is unstoppable.
Or maybe Player C will realize that he is kingmaker and can put either A or B over the top, and uses this leverage to call for a draw?
That is classic Diplomacy, and while most often I think WarLight games will end in single winners, occasionally, in Diplo games, you might have very exciting endgames.
Edited 8/2/2016 00:34:52