I agree that using one technique for an infinite world is probably going to get boring pretty quickly, and you can probably get more leverage out of a finite world.

But even with an infinite landscape, I think you could improve the variety by using a generator at different scopes - if your landscape is just one constant type of terrain, like a field, things will get boring. You might have a wide variety of rivers and trees, but the basic idea is the same. But if you have another generator controlling the terrain type - going between plains, desert, mountains, etc., that would be really interesting. At the small scope, variation in trees and water is still the same level of change, but there is also a larger scope that changes the overall feel at a much larger radius.