Imagine an online coop style FPS or TDS game where say 2-6 real players fought large amounts (20-60 concurrent) of AI enemies. Could this style of game be reasonably networked over the internet using a Quake or Tribes style partial state replication model? Almost every coop game I know of uses a lockstep style networking in these cases (even games like Halo which use state replication for normal multiplayer, but lockstep for coop/firefight). My concern is that the network download (for clients) and upload (for server) overhead of each AI would end up being about the same as if a real player was in the game. Is this a real concern? Or is the limiting factor on the number of players more about how much data the players upload?
TLDR; Can large numbers of AIs be reasonably networked to a few players with a partial state replication model or is lockstep the only real solution.
Any help here would be great!