With regards to the skin colours, well, Morgana can look like however she wants (she is after all, either a goddess, a faerie shapeshifter, or a powerful enchantress, depending on the source material). Arthurian legend also has had characters from various ethnicities in it.
This seriously looks like a choice for "modern audiences".
If this by chance was just a creative choice and had nothing to do with that
it's still a bad choice these days considering people start to get really annoyed with all this modern crap.
You will only damage your game. After all adventure games are a niche genre.
Can you really afford to lose gamers?
Actually yes, we can. Because we don't make games for a living, we make games for fun. In terms of how much we've made from games all these years... it's really been pittance.
And I get it; I don't like tokenism. I work in a male dominated industry where most people are white middle aged males... and I'll often be the only female in a meeting of 10 people. There has been the odd occasion where I've been asked to do a photoshoot, where I can tell they are specifically looking for a female with coloured skin to promote that it's a diverse company. I actually take exception to being singled out like that, as the focus is then on the appearance rather than who I am as a person.
But in this case, this is just a game with its own story telling... and I trust that Radiant would have developed the characters enough that it fits the story and isn't just a character that has been given a different skin colour. Radiant is always very particular about details and that all feeds into the way he designs the story, setting and characters.
As for the portraits, you'd need to be more specific about what you don't like about them. I can't really improve anything without specific constructive feedback.
Arthurian legend also has had characters from various ethnicities in it.
I don't know how legit this claim is, what are your sources?
Unless this is meant to be a parody.
It's a comedy and has a bit of a Monty Python feel to it. I haven't read the full legends myself (though Radiant has), but a quick Google supports that other races were noted and known of in the Arthurian legends (i.e. there were characters of colour written into the stories).
From a historical viewpoint, the Middle Ages arose after the fall of the Roman empire, and the crusades occurred in the Middle East. The Roman Empire itself spanned a huge breadth in its heyday, and so if the Romans knew about Africa and the Middle East, then surely the author(s) of the Arthurian legends knew too.