Hey Saltiest Knight! Hexes are fine, but I think squares are more accessible for most players--and in a game where keeping track of distance and ranges is of tremendous importance, I think squares make that aspect of the game a lot easier. (As I put it 12 years ago: "Hexes offer greater versatility of movement; squares make it easier to visualize distance. Each has its advantages.")

This is doubly true for a game where facing matters. I think backstabs are just a lot more intuitive in a left-right-up-down environment vs. one where characters can face up, down, up-right, up-left, down-right, or down-left.

There's also the matter of cost. If characters are 2D assets, using hexes means either facing needs to be taken out of the picture, or else you're looking at rendering every sprite and animation in two additional directions. (That said, I mayyyy not be going for 2D characters on the next title. 😉)