While Litchi will tell you which way the AC is pointed AT each waypoint, it will not show you where the AC is pointed as it flies BETWEEN each waypoint. The preview function in Autopilot lets you watch the AC rotate as it flies between each waypoint. Since Litchi doesn't allow you to modify AC orientation between waypoints, it's not too hard imagine where the bird will be pointed as it flies, so having a preview isn't a big deal (although I'd still love to have it!)
Autopilot lets you set "focus triggers" between waypoints which affect AC orientation. This makes it more difficult to predict exactly where the AC will be pointed as it flies, and so the preview function becomes even more valuable.
I would love such functionality. It could easily prevent a crash.
Unfortunately, the preview in Autopilot won't help you prevent a crash. It's still displaying a 2 dimensional map and only shows the AC's movements in 2 dimensions. The preview gives you no altitude or obstacle avoidance information. It would be very cool if it did!
A "filter" of some kind in Litchi which could look at Waypoints in context and flag one that has a zero altitude whilst the adjacent Waypoints do not.
That might be a good reminder, but it isn't failsafe. The altitude of Litchi waypoints is relative to the home point. I recently did a waypoint mission where I wanted the bird to be 20 feet above ground the entire mission. The ground sloped throughout the mission such that the final waypoint was 26 feet lower than the home point/1st waypoint. so, waypoints 1-4 had positive altitudes (20, 19, 18, and 17 feet respectively), the altitude setting of the final waypoint was -6. So zero altitude, or even sub-zero altitudes can be safe and legit. If a user did a lot of that type of mission, having Litchi constantly bleeting at you would get old real fast. Perhaps if there were an option to turn that warning on and off....