Tonight I've become the lucky owner of a lightweight M4 with competent, destructive, ferocious (only 18% EAD native but the latter talent easily negates that) and a Lexington challenging field test was extremely satisfying!
For a future classified AB build it might be nice to add focused to the mix for doing even damage, with or without skills on cool down (although there're likely some better talents out there for an ever present flat damage). - - I miss the old 6 talent AB :/
Adding to what gamble said, I wouldn't even go full sniper because, despite the weapons being present, the game is too fast paced to present sniping opportunities IMHO.
What's the classified drop rate in the normal pool? Got 2 tonight while messing about whilst getting a tonne of green.