Kotoamatsukami is pretty powerful...
The reason Mifune was freed was because Danzo freed him. I know Itachi programmed the crow's KA to command only "Protect Konoha" , but that doesn't mean Danzo was not controlling Mifune sort of like mind transfer where you can make the person do multiple things before the jutsu is undone.
I think Danzo was using KA the whole time (rather than just give Mifune one command). My thought is that Danzo was using KA and still controlling Mifune and feeding him things to say in his mind up until AO started explaining the jutsu and Mifune snapped out of it.
As you could see , Mifune performed more than just one argument during his time being under KA. He not only pointed out the flaws of each Kage and their village, but he also recommended Danzo for the role as Leader.
Some could argue KA still had a lasting effect on Mifune because after AO's intervention, Mifune still alluded to wanting Danzo to be the leader of the alliance in the first place.
Itachi only gave 'his' KA one command because it was in a small crows body and there wouldn't have really been need to order anything more than that because all he wanted was for Sasuke to protect konoha. Even if Obito told Sasuke about Itachi's secret, Sasuke probably would've blown it off (like he did in the cave initially) as Obito "Madara" telling lies. Its still just a genjutsu overall, so its not unstoppable.
Some people think you don't need eye contact for it to work on your target. I think its more like a stealth jutsu , as in hiding in trees or something when your opponent doesn't know your there.
The big plus about it is, unlike the sleep genjutsu Kabuto used at the stadium where Gai and Kakashi & Sakura noticed and released the genjutsu, Kotoamatsukami works like its your own brain's ideas as opposed to just following orders. Or unlike Itachi's genjutsu where he told Kabuto to show him the signs to undo the edo tensei, KA doesn't require the user to speak at all. They can just think commands, and there you have it.