Newbie here, hope this falls into the right category,
there are two things that might be a great addition to the QGroundControl software.
For one, a sort of “Get height” button from google maps maybe (maybe via right/long click) that tells you the height over 0, at that point.
In addition to that something to review the flight plan height on a graph, compared to the height over ground. So that you can be sure, for longer flights, that the height difference doesnt drive you in the next hill. If there is a “keep x ground clearance” feature, that’ll work as well, i havent seen it yet though. A Workaround would be loading the KML into google earth and viewing it in 3D (that requires absolute heights to work)
Also: Deleting points by clicking “x” or “delete” would be great!
Side note: i cant figure out the loiter landing mode which is described in the “new features” page, that isnt too urgent though 
Im sorry in case my english wasnt too easy to understand, im not a foreign speaker 