There may come a time in the map-building process when you're wondering how much cover may be afforded in certain spots. If you're lucky enough to be in an online multiplayer editing session, and the other players will listen, you may be able to instruct one of them "Hey, stand right here where I am now for a while" while you check how well-covered that spot is by proceeding to take on the role of the attacker, examining the view you get on them from various angles of approach.
It would be much simpler to carry out investigations like that if edit mode gave access to a command inspired by the Elegy of Emptiness, from Legend of Zelda: Majora's Mask. Basically, this command would spawn a temporary grunt at whatever location you happened to be on. This would just be a temporary player, not an entity that gets coded into the map file or anything, and it would have its movement speed scaled down to 0, though it could still take damage and get pushed around by weapons. That way, a single player even in offline editing could perform these line-of-sight tests using actual character models on both ends.
A grunt spawned this way should persist even if its "owner" switches between playing state, editing state, and spectating state, but should disappear if it runs out of health, hits a kill plane such as lava, or if its owner disconnects from the server. To prevent the command from being used maliciously to flood the map with hundreds or thousands of characters and cause lag, each player should be limited to one summoned grunt at a time, just like the real Elegy from before: if you use the summon command when you already have one, the old one disappears so it can spawn at the newly requested location.