Well, Jorb and Loftar were talking about weather systems and things like that, I came up with what might be something of a fun idea.
In lieu of the talk of meteors and such, and people wanting something renewable, I thought "Well, what if new meteors just happened to fall?", Simple enough, take it a step further, sending a flash of light in the nighttime icon at the top of the screen to everyone in that region, meaning everyone who was in that region at that time knows a meteor just fell, and could go out to try and find it. If we wanted this to be even more fun, Meteors could strike in a random place, and destroy objects. (Although probably not within village/player claims.)
For people desperate for metal, this would be like a sign from the gods, and would mean everyone in that village would jump up to go out and search for it. Not to mention it adds a bit more variety to things.
As for the veins of ore, well I would just say let Rain be the factor that washes up those vains, meaning after a rainstorm people might check their mudflats or mountain areas to see if the rain uncovered a new vein. Just something to ponder on, and once again, to add variety to an otherwise fairly dull and straightforward system.