The roots you guys implemented to "grow" under dirt blocks, they're pure awesomeness. Don't underestimate the little and inconspicuous things, they add a lot to the entire atmosphere.

 

That said, it would be very neat if those root would randomly sprout in a radius of xyz blocks extending from the player (to limit the load on the system). As it is now, they seem to be once decorated and that's it. End of story.

 

But what if you mine and leave a tunnel or tunnels of dirt behind you, and then some time later you come back and roots are everywhere.

 

Well, it'd have to be so they "spread" from other roots, but if it was made so that the radius was decently sized (Like 5 blocks from the root), but they spread at a slow speed (Like, a lot slower than grass spreading), it could be pretty cool.