How Big/Detailed Should A Randomly Generated World Be Anyway?

[GGambrel]

Hello!

So as the title suggests, I'm looking for opinions regarding randomly generated worlds for a long-term project of mine. For instance, how big does a world map need to be to feel "vast" from a player/GM perspective? Is that even desirable for most campaigns? Do you think it advisable for a generator to create much beyond the terrain or should that be left to the GM? If so, what kinds of additional features (territorial control, populations, points of interest, etc) do you feel would be the most worthwhile to include?

Background: I'm envisioning an overworld map for a planet roughly the size of Earth covered with "tiles" designating a type of terrain. After the overworld is generated, I'd like to include functionality (or a separate program) to generate smaller maps for these tiles based upon their terrain types. Perhaps down to sub-tiles a mile in width? I suppose in principle a generator could be built for points of interest as well.

I'm just looking for input as to what people think a good world map generator should be able to do. Thanks for any suggestions!