I think they finally have, I just got my 14.5" & 18" barrels barrels replaced (for the second time) and these ones are nice and tight and the accuracy with heavy bullets is very impressive. My new barrels are the standard NEA mid-heavy profile with the spiral fluting, its not very deep and only aft of the gas block so it doesn't do much other than aesthetics. I think something like the deep straight flutes like whats on the Maple Ridge barrels would be awesome on the NEA barrel profile as long as its done on both ends of the barrel.
Ideally I would like to see NEA change to a rifle length gas system for the 18/18.6" barrels as the mid-length is severely over-gasses and often rips case heads with heavy 5.56 loads. An H3 buffer helps, but it's not near as soft as a rifle length system would be. Would also like to see a 1:8" twist to improve accuracy with lighter bullets.