While the Surface Duo (and maybe the LG with a 'snap in' screen?), it won't be the last.  It's a fantastic concept and I would expect much more to come.  Now that the beta of iFly works on the Duo in single screen mode, a few ideas:
Ideas for iFly:
 - Take advantage of the dual screen spanning once fixed. Just full screen map and you can rotate both directions....simple
 
 - Consider the split screen for just about everything...(I'm using left/right, but should be completely user selectable)
 
 - map on left, flight plan on right
 
 - or when tapping an Airport or airspace on map, load the details on the right. (keeps map uncluttered)
 
 - or map on left, instruments on the right. (keeps map uncluttered and instruments easily readable
 
 - or map on left, terrain profile view on right
 
 - or have button bar on left, but tapping NRST, loads all airports on the right.  
 
 - Map on left, scratch pad on right
 
 - 3d EFIS on left, map on right
 
The advantage of these is larger tap targets when in a bumpy airplane. Unrelated to the Duo, I do wish iFly had a bit more robust Vector map and layers.  I just love Foreflight's implementation.  Same with a good Logbook and more robust Weather planning (MOS, multiple days out forecasts/etc.). 
Thanks!
John