Where a deaf actor has the necessary skills they should be considered. Unfortunately, most films are not there just to promote various areas or raise direct awareness, inclusion isn't a reason to insert a deaf awareness campaign and offering lectures etc on how to do that, which sadly seems to be vogue for those deaf who do get included in media, it near always turns into 'deaf do this, or Deaf do that' etc, which may have no point to the actual story being related. Inclusion isn't an excuse to launch into an awareness campaign and disrupt the point of the story.
As it usually is, it is the sign using deaf who complain most about these issues. They complain if a CI user is included who doesn't sign, or a lip-reader who doesn't, via the 'Deaf do this..' approach, which isn't inclusive, what they mean is SIGNING deaf do this but other deaf actually don't. Which a film maker won't feel has anything to do with his or her tale.
Raising the temperature somewhat! there are issues of education and experience, while a deaf actor may be well versed in the deaf community and culture etc, to participate in an area where it doesn't, raises issues of relating to other actors. So many deaf only relate to other deaf, so the first hurdle to overcome is to use deaf actors who can live/work equally and without issue with hearing etc.
Deaf acting will 'arrive' only when nobody notices they stand out to anyone else. I rather fear the Signing area sets 'rules' that make their hiring problematic, they aren't really hired or paid to tell people they are deaf or to highlight sign language, [except in areas dedicated to that]. There is, of course, a box office reason to hire hearing to do deaf jobs, especially if they are profile actors who can 'bring in the money' because they are more widely recognised.
Media isn't a charity. The root of it all is a lack of deaf-hearing experience and, it tells. We know 'Deaf do this..' etc but hearing, DON'T, so we need to fit in. Also hearing constitute the majority of paying audience. Deaf are a minority, it is, how it is.