I don't think each Soldier life should be one death. Soldiers are designed to be squishy/less powerful, but have 3 lives in return. Their 3 lives are basically one life of a one life class. Giving them a death for each life would be like giving, for example, ARCs one death for each 66 points of armor/hp they lose (they have 200 armor/hp max).
On the point of score system points, it should be like this:
- Damage should increase score points
- Teamdamage should decrease them
- Kills should increase score points
- Teamkills should decrease them
- Assists should increase score points
- Negative teamassists should decrease them
- Doing the objectives should increase score points
For every each one of these the score points gained/lost should be displayed along with their corresponding messages, except for damage and teamdamage which don't have any messages.
Edit: The message for teamdamage ("Don't attack teammates!") should also say that your score points were decreased. I've seen this message having "Your points have been deducted." after it in jaMME with an older bugged cgamex86.dll. See the beginning of this video where it is shown: