We have the same issues, and hope that DD has put this towards the top of the develop. plan. We've also come up with some techniques to overcome this.
Everyone always want to fly as 'nap of the Earth' as possible, but the closer you get to the ground the bigger your issues become. In fact the closer you get to the ground the issues quadruple. So first thing to consider is how high a resolution do you really need?
1) So we fly a P4P and it's camera has a 94 degree FOV. Given that and a little bit of high school geometry, we get;
* 100 ft = 0.5 in/px
* 200 ft = 1.0 in/px
* 400 ft = 2.0 in/px
and here's the kicker, if you're providing your Customers 2 inch Orthomosaics, because the file size is reasonable, then there's no reason to fly below 400 ft. But we all do anyway. That's cool.
So next thing to consider are those 2 pesky FAA requirements, fly no higher than 400 feet and always keep the drone in sight.
2) With regard to line of sight, we find it's hard to keep sight of our drone much farther out than 1500 feet out. Now with some grade school math that's about 120 acres. So for a lot of us you need to break up the mission into multiple flights. And I'll bet most of us split those missions into flights by field boundaries and or to get around trees or such.
So having read so far, the answer is fly by contours. Check it out, Using DD's elevation map;
The map shows, how we used to fly the area, by block boundaries. Now because we want the best resolution possible we split that into 3 overlapping flights based on the elevations in the area.
3) And lastly, with regard to that 400 foot altitude restriction. If you fly in any kind of hilly or mountainous terrain it's hard to not violate that rule occasionaly even when flying well below 400 feet. What we've done in the past is try to stand near the top of the area and fly from there, and if the drone is at more than 400 feet at the bottom of the field, well stuff happens. What we now do is stand in the middle of the area to be flown, and adjust our altitude from there.
And remember, always give it more lap!