Alien races actually find the masked Ren LESS intimidating than they do Hux or any other unmasked officer of the First Order, as humans are Galaxy-spanning parasites that most sentient races secretly find TERRIFYING (we destroy planets in our wars!), and keep requesting his presence at peace talks/negotiations of surrender/parties. I want alien races giving Hux the side eye and chatting up Lord Ren, in all his Vader-esque glory, to the increasing distress of both.

Bonus Points for Ren knowing what other races think of humans, and just assuming that's why most First Order Officers don't wear masks - to scare the locals.