I think one interesting way to add a little variety to the game is allow for more dynamic settings, for example:
Board Size - allow a range of board sizes
AI - there's something to be said for scaling AI, but perhaps you can also set it to something within a given range
Unit Types - I hear a lot of people complaining about different units being far too effective etc... like assassins, personally I don't see a problem with them... But rather than hearing these people complain, you could put in settings to allow/disallow certain units...
AI Start Locations - in coop, the AI really is pretty easy no matter what difficulty, as long as your both pick something that works well together giving the AI more starting locations would allow them more spawning points, which would actually make the game more difficult. Rather than selecting how many 'castles' they get, you could select how many 'deployment spaces' they get.
Templates - the ability to turn on/off certain or all templates
There are probably other settings that could be made more dynamic to allow the players some control over how they want to play, etc... Regardless, its something to think about...
Board Size - allow a range of board sizes
AI - there's something to be said for scaling AI, but perhaps you can also set it to something within a given range
Unit Types - I hear a lot of people complaining about different units being far too effective etc... like assassins, personally I don't see a problem with them... But rather than hearing these people complain, you could put in settings to allow/disallow certain units...
AI Start Locations - in coop, the AI really is pretty easy no matter what difficulty, as long as your both pick something that works well together giving the AI more starting locations would allow them more spawning points, which would actually make the game more difficult. Rather than selecting how many 'castles' they get, you could select how many 'deployment spaces' they get.
Templates - the ability to turn on/off certain or all templates
There are probably other settings that could be made more dynamic to allow the players some control over how they want to play, etc... Regardless, its something to think about...