NA sounds very good to me. I think there is a lack of more interesting and varied terrain for DTO. NA villages, rolling hills, Italian forts and patches of cultivated land (based on oasis) come to mind for Libya. Then there is the mixed temperate-desert terrain of Tunisia and the coastal margins all along the Mediterranean. Definitely need more large NA hills.
Getting away from NA, one type of terrain that is practically missing from ASL is the open Steppe type (in green). The closest official boards to that are t, x, 16, 18, 19, and 33, but are still too cluttered compared to photographs from Ukraine. CH did 3 boards in Dien Bien Phu 1st edition (D1, D2, D3) that are the nearest, but (a) are likely difficult to find and (b) full of shell holes. The use of desert boards using Steppe terrain type still leaves too much woods and brush due to the conversion of hammada and scrub.