Two guys logically explain why The Boss, a middle-aged war veteran, does not look like a 20-year-old e-girl
Gamers: Well she should look like one anyway
I'm so tired 
It's so fucking stupid, she looks pretty much exactly like the original character but in a photo-realistic style
Holy shit, I somehow missed the most unhinged comment:
[CW: Transphobia]
spoiler
They made the boss look trans and that's a fucking crime.
The chin is different, it looks like a man's chin, the mouth is different, it looks like a man's mouth, more specifically it looks like Chris Chan's mouth, don't believe me, go do an image search. Neither the mouth or the chin or the brow or forehead or zygomatic process feminine in any way in the remake version.
The boss has deep cheek hollows because they changed her maxilla as well, literally everything they did was to make the Boss look like a ******.
Their brains are so fucking cooked
To match set and environmental design and how that's shifted with rendering technology? The original has this "overcast day diffuse lighting, supplemented by reflectors and artificial lights" kind of look, the remake looks like a normal day - that says the intent with the original was not "everything is always cloudy and diffuse in a way that's just perfect for photography" and that was just a concession to the lighting and shadow rendering tech of the day.
As for hair, who knows, though I'd guess based on the way the hair is nearly identical where the light is harshest they may have decided that changing it actually makes it match the look more: compensating for the brighter lighting and the lighting interacting with the hair by darkening it so it's brought back to the same level. The original hair tone was likely washed out and wound up looking white with the modern lighting engine, or something like that.