I agree. but if you consider that unconscious units do take damage from fatal wounds, my guess is that implementing environmental and blast damage was not omitted intentionally, but instead because it wasn't a priority.
I'd say that it doesn't need to be in right now, but care should be taken that the code design allows for adding it later / as a mod. I don't know, maybe by creating a different type of "item class" for unconscious units instead of just turning them into items completely.