Random events?

Random isn't even an option. Random things, especially on a game changing scale, are not appropriate for RTS. Fixed events are not bad, as long as they are persistent or at least consistent.

World events are the real question. What sort of events can be allowed, and what would they do?

One of the few examples of a stable, game changing event are the destructible rocks from SC2. These rocks may not be sexy, but they either close or open up new areas of the map for players to fight over.

This is also one way of setting things.

There was a discussion about a bunch of non-random events, namely "Sudden death" variants. To limit the game's timeframe and add come action. But this events are more or less game mode controlled, far from "random".

And about destructable rocks thing - you have one such thing already. It's called "metal planets".

the most obvious thing is that if you have a planet that has a possibility to get pelted by asteroids, why the h*ll do you have your commander on that planet! if you are so worried that an asteroid will come flying down and blow your commander up, why did you have him on a potentially lethal planet to begin with