The ability to set your own number of vertical and horizontal grid divisions, preferably with an option of forcing 1:1 scale. While the current grid corresponds with the underlying format of the cues file, there is no reason to be limited to this grid. A different grid can handle notes in whatever way off-grid notes are currently handled. The current grid has way too few divisions to rely solely on. It is also not 1:1 scale, but close enough that it's not overly obvious to new users. Inconsistent grid spacing can result in inconsistent note spacing in patterns, which is not ideal.
Originally requested by @Zernys in #86