I'd love to see giant battles (1000+), but I don't think it's possible. Massively multiplayer games are set up differently than most action games like Mount & Blade. In a MMOG, players are only connected to the server, and the server handles sending all game updates to the client. So if there are 1000 players, the server is handling 1000 connections (1 for each player). In a game like this, where having a low ping is really necessary for good gameplay, there is usually a client to client connection. This means that each client has to manage a connection to every other client, which doesn't scale nicely.