This article was written in reply to a developers comment on IndieDB :
You said you might drop the notion of modding because it is an MMO game:
Moddability actually is out of question, since it's an MMO I need all the clients to be Vanilla.
I would like to present a number of arguments to the contrary, just remember that the above choice could still be the right choice.
There are two starting reasons for being able to Mod a system:
1) An Offline prerequisite for development: Modding is a way to switch assets in and out the game at a whim. Imagine that Chinatown is south city in your game and you are in Little Italy: Suddenly you think to yourself, what if the Hispanics controlled the Boulevard between - Hit the mod key, type a command and presto they have driven a wedge between the two factions - and you are still in play mode with a re-code, re-build slowing you down.
You can remove your Mod Interpreter from the User Download Files and keep it purely for development purposes.
2) For the Players, the Players and to your advantage.
a) A person who is there to Mod is there to stay - a resident, a community advocate and WOW maker.
b) You control what to Mod: The interior of Player homes - or an block controlled by a Guild/Faction might be dressed to their tastes. This will not affect gameplay but provides WOW. Imagine the city of London, the house of Parliament remain unchanged maybe some burnt out double-deckers on a bad day. Or New Ork whose skyscraper are still etched into the night.
c) Trickle funds: Its hard to get cash to keep Servers running. A little asset store promoted by the Modders themselves keeps your ball rolling.
d) As above, plus FREE TO PLAY and or FREE TO WIN
e) A City to Themselves: Keep your Vanilla servers but provide a place for people to Showcase and you to source talent.
f) Longevity: Who knows the Modded Sever may be the only Server left standing when your success winds down.
Modders of the World, I salute you,