If FOC is too low, the arrow will be unstable in flight. It will take longer to stabilize after launch. Wind will have a much easier time blowing it off course. A very small unseen twig will cause much more deflection than it would with proper FOC. It will make the bow harder to tune. It will make the bow much more critical of shooting form issues. Broadheads will magnify those issues

You can tune and shoot accurately with such an arrow, and a lot of guys do. My masochistic streak doesn't run quite that wide. I'd suggest going to a heavier head, or switching to feather fletch if you're using vanes.