But Fire Emblem is all about having complex, sympathetic player units fighting for your cause. Playing through maps and managing to keep all of your units alive at the end is one of the fundamental aspects of being a Fire Emblem fan. If we were left with generic, nameless characters, then this series wouldn't be any more different than the Nintendo Wars franchise, which has you sending squads of soldiers to their deaths as a viable strategy.
However...if you really do crave for something like that in Fire Emblem, then I guess Shadow Dragon is right up your alley. It has dozens of named characters who don't get so much as a single line of dialogue (outside of their death quotes), meaning that you can freely kill them without a second thought. Also, in order to get all the characters in that game, you actually need to kill some of your units so that you can unlock more chapters to play.