If procedurally generated worlds were the answer, everyone would use that solution (while no one does). Making a procedurally generated world is actually easier, faster and less costly than making a world that needs to be manually designed from the ground up.

The side effect, though, is what you get in Fuel. The world is BIG, yeah, but it's extremely bland, and it's not optimized for it's purpose. For instance in Fuel you notice quite easily that the world isn't designed around the tracks (as it should be for a good racing game), but the tracks are designed around the world, making them rather poor for gameplay use and simply not fun to race on.
On top of it,unless the developer actually gets around tweaking every single world element and decoration manually to make up for the obvious misplacements and problems created by the fact the automated world generation, you end up with glaring flaws (of which fuel had plenty) like floating rocks, compenetrating trees and buildings and things like that.

It's a cheap way to get immense worlds, but it's not a be all, end all solution,especially for a world that needs to have gameplay elements installed on it.
In the end, art direction-wise, manually designed worlds have a TON more potential to be actually interesting than procedurally generated ones.