If most fights resolve at less than 15 squares, I'm just not seeing it as a terribly important choice.
That's exactly my point, if it's irrelevant, why are you adding extra complexity? Just be consistent.
That said, I have nothing against making the field of view an octagon with points on the diagonals and orthogonals. But if I do, will players be annoyed that the field of view is the accurate w/r/t movement octagon rather than the accurate w/r/t expectation circle?
It's a matter of which is more important, making your system consistent, or making it look a certain way. (filtered through your understanding of your players desires perhaps)
To me, an inconsistency like that is simply unthinkable in a game intended to be tactical.
