OzzyKP
Emperor
I am not sure why you feel having allies in the game is not meaningful.
2 Players fighting together always brings benefits ... so why do we need more?
I would actually be worried that anything more would make it OP.
Perhaps there could be some scripted events that would produce units to ambush invading royal troops or something? My expectation, based on what I know of the AI, is that any allies would just send units wandering around haphazardly instead of making a tangible impact.