My opinion is that it need some workout. The issue of being griefed by other people using terra-forming is something that we can avoid by limiting the height of the ground people can raise base on their level, for example for skill lv 25 we cannot raise the "slope" too high that people cannot jump over or climb.
This idea is being used in Wurm and it turn out to be so efficient that there is no need to limit people's terra-forming skill in their own tribe, which also lead to huge awesome project such as canals, tunnels and mountainous road.
Also, their dirt weights relatively heavy, so nobody can easily carry them without a cart, and it is in fact realistic.
Instead of just making it easier, why dont we change it completely?
In short, my opinion is: harder terraforming for newbie and low skill players, quicker for the labor forces, the professional players.