“To me, calling the departed a korbon, focuses on their last moments, instead of their life. ”
Quite the contrary. A person does not become worthy of being considered a korban tzibbur overnight.
It takes a lifetime of sincere devotion to come to that level.
Saying that the deceased was a korban, indicates that his entire life was extremely admirable.
But, in any event, as I wrote in my very first entry, once we see that the Gedolim (Harav Cohen and HaRav Edelstein) used that term for consolation, we have no option to doubt that what they do or say is correct and proper. Although one may argue that it is ok for them to say, but perhaps not for us to.