There are three types of changes that will need to occur throughout the lifecycle of this universe. Each is equally important to plan for.
These types of changes include cosmetics and guild-defined quests, none of which change the core rules of the game being played by everyone, but provide a critical layer of cohesion and entertainment.
While these changes do not change the fundamental rules of the universe, they do provide an influence over how those rules are enjoyed.
These types of changes include unit-type definition and tweaking of current sinks/taps, both of which must be done with caution (one more than the other) but should have clear and clean processes in which they are done by the community.
These types of changes include bug fixes, the addition of new resources, new battle mechanics, and other changes that fundamentally alter the game for all players.
These types of changes require significant consensus by the community, clear testing requirements and results, and careful roll out procedures.