On-Topic: I don't think lossing limbs fits on esf. Anyway, it would be great if after getting damaged down to an percent of health, the character model, still, running and walking animations change into another to reflect that he is actually damaged.
Plus, but it can be too long to do, is adding different animations for attacks when you are damaged. For example, if you are at 100% health with gohan and you do a kamehameha, he will do it like Goku, but if you are, for example, at 30% health, you do the kamehameha with just 1 hand, like the powerstruggle in the cell saga vs cell. I think this can add imersion to the game.
Off-topic: To stop controversy about from where the GoldSrc was created, here is a picture of the evolution of the id engine, including the GoldenSrc:
Quake Family Tree
Have Fun ^^