This is perhaps a bit over the top, but there's a nice talk on how Naughty Dog made Ellie as non-annoying as possible in The Last of Us:
Dealing with large numbers of followers... it's a tough problem unless you disable collisions or make the collision volumes tiny. Perhaps in confined spaces have a minimum follow distance. If the player goes too far inside the minimum follow distance, the whole column of followers back up. I think not breaking stealth is quite important, maybe they try to stay in cover if you're sneaking, and the enemies ignore them unless they do anything too blatant.