I'd like to see it possible for a 'one city challenge'. From the beginning of WoM many thought that there should be an alternative to city spamming. Early on in WoM (my memory may be somewhat faulty here, my apologies for any mistakes) our sovs started with a set amount of essence, it cost essence to found a city (cities not in our existing territory anyways), essence was needed to give champions the ability to cast spells, and unspent essence would power spells. This gave us the choice of 'many cities/champs + low powered spells vs few cities/champs + powerful spells.
I'd love to see something of the above. I'd love to be able to have only 1 city and a couple of champions, and still be competitive. Currently that's not possible. Even with outposts to claim resources and shards, and outposts being upgradable (a very nice feature!), because the city is the 'developer' of the resource/shard/outpost upgrade, 1 city would have to build buildings, recruit troops, develop resources, and upgrade outposts -- not possible in any reasonable time frame.
Possibilities (numbers are made up for purpose of discussion only):
-Sovs start with ~20 essence (magic 'heavy' sovs more, magic 'light' sovs less)
-1 essence per city (no matter if founded in or outside of territory)
-1 essence per champ (all champs now are casters, if we went back to having to grant spellcasting to champs then make the essence cost for granting spellcasting and not for recruiting)
-rare locations that grant +1 essence, and possibly sacrificing champs for essence
-unspent essence would power spells (extra 10% damage/range/etc. per point?), increase build rate (ie -- increase production/research by 10% per unspent point?), etc.
-outposts would be the 'developer' of any resources/shards in said outposts' zone, and also be the 'developer' of any upgrades to that outpost (taking this away from the city). Outposts would otherwise not substitute for existing city functions.
Remove restrictions of city building so 1 city could build all possible buildings
Goal is to add choice -- empires with few cities would be able to compete with many-citied empires.
Can the above be modded in, or would it require an official expansion?