While I'm going to be too busy for the next few weeks to be a part of any rides, I'm going to toss my two cents in. I think any ride should incorporate more natural features than man-made. Why? Because most man-made features are optional on a trail whereas the natural features are usually directly on the rider's path. Log piles, rock drops, natural berms, exposed bench cut trail, and roots are all more common than even a 1 foot high TTF. I know the skills are pretty much transferable, but actually applying the skills can be difficult.