Hello,
Last night, on "Science Saturday" (we need an AAR forum for Arma 3), there were huge noticable hits on the server when there was AI present, due to the Arma 3 alpha currently not supporting dedicated servers. This lead to some very strange behaviour (Everyone died without any glory all of a sudden).
However, in Arma 2, when the AI is controlled by a player, the calculations for that AI are done client side (by the player controlling them). I am curious if this would be the case - Puppeteering, like done in some folk Arma 2 missions, could be a workaround for the problem described above.