Is it possible to change unit names such as "Giant Death Robot" to something else? I understsnd how to rename units, but would like to change what appears in the production queue. And can messages such as "People Who Smile the Most" be rewritten? I was surprised to see such casual language and prefer the more traditional.
It's possible to create a mod for Civilization 5 which changes texts. The method I would recommend is to setup a new language for civilization, and replace and strings you want changed in there. That way you can always switch back to English when needed, and you have a backup of original texts.
Thanks to Xenox's answer I was able to change "People Who Smile the Most" and others following this path:
C:\Program Files (x86)\Steam\SteamApps\common\sid meier's civilization v\assets\Gameplay\XML\NewText\en_US.
Use notepad to open the file, edit the changes, save and run the game. The same applies to "Giant Death Robot" (under units) which became "MechWarrior." The name seemed appropriate and is much more menacing.