Yeah, really, 5-6 years later there is enough of hardware to run this game with facial animations and ambient animations(aka first RO2 trailer with church), and by the way it would be very very weird not to include any of theese after KF2 with facial animations for Zeds, so I dont really see a problem implementing them.
Almost every game after 2013 have facial animations , take a look at Bioshock Infinite, of course its AAA game, but still , it does have everything, and its built on UE3, what a pleasant suprise, and works quite good on wide spectre of hardware.
The only one reason why AMG couldnt make them might be the lack of time, other reasons are excluded.