A lot of my work leans more towards realism, but I do dabble in anime art occasionally. I think a lot of people's issues with front-facing views is how unforgivingly symmetrical the face can be, especially the more stylized the art is. Those perfectly symmetrical faces can look very unnerving, especially since it implies that the character is turned directly and perfectly towards the "camera", which looks quite unnatural (and often used in horror pieces/film actually LOL). Having the subject slightly tilt their head up, down, to the side, etc, can make the front view feel less "targeted" and more natural, since it also looks more like real-life portrait photography. It can be really slight, but imo it helps a lot.
There's also the whole "real-life faces aren't usually symmetrical" thing but when it comes to stylized art (especially anime), I don't think that's what contributes to why some stylized front views look weird. Imo it's just full-on symmetry making it feel like the character is staring directly at you in this weird robotic/inhuman way. So some deviation from that helps.