First let me apologize for repeating what others may have written before. I don't claim any or all of these ideas as my own - but the squeaky Wheel gets the grease, and this wheel ain't been greased in 8-9 years....
Graphical column schedules (and columns in general) are something that structural engineers need for nearly any large project. But they have some major shorthcomings that need addressing:
1. Column Location Marks - These are the root of the sorting algorithm that graphical column schedules use, but there are issues in these hard-coded (and API unchangeable) values that can cause some serious headaches. In concrete high-rise projects, it is not uncommon to use grids on the face of columns as opposed to center of column along the perimeter of the structure. But the grids along the face of the often are not "read" to the column location mark when other grids happen to cross thru a column closer to the center. Even more confusing is when a larger column transitions to a smaller column higher up the structure, and the two different column sizes happen to associate to two different column grids because the column centers are not aligned and happen to be closest to two different column lines (neither of which may be the one you want association to..). So not oly doe the columns read a column location mark that may not be the one you want, but the column "stack" may not even read as a single stack because the first 15 floors of a column stack may happen to associate to a different column location mark than the following 15 stories. So request #1 - we need some way to override the Column Location Mark. I would like to see this be something a bt more "complicated" than simply typing in a new mark. It needs to be some sort of an "associate grids" command (or API method) that requires a bt more thought and "stickiness". Without this item being addressed - Revit's graphical column schedule capability can never really fully meet the needs of structural engineers. Note that fixing this issue might have other benefits as well for other workflows.
2. Column stack ordering - currently we can kind-of specify "Column Location Start" and "Column Location End' - but who's to say if that represents the order that we want the column stacks to be shown in. Often we might want certain areas of columns grouped together. Other times we might want certain columns (say along a parking deck ramp) shown side by side to illustrate the different column pour break locations along the ramp. Ideally - I would like to be able to highlight a column schedule "column" (the vertical boxes in the graphical column schedule - not the structural element) and choose "move left" "move right" and " hide".
3. Structural column size representation (view angle) - Currently there is no way to control how a column is shown in the schedule in terms of the direction it is viewed from. If a 24"x48" column transitions to a 24"x36" column and later a 24"x24" column, depending on the direction that the transitions occur (N-S or E-w) the column may show the transitions in the schedule or it may simply appear to be a consistent 24" wide column all the way up. Idealy - a tool to handle this should not be a simple "show E-w or show N-S view" but should be something where we are allowed to "pick view parallel face" in order to handle columns that may not be aligned to a N-S or E-W orientation.
4. Allow graphical column schedules to be rotated Clockwise and CounterClockwise when placed on sheets. When dealing with buildings over 20 stories, it gets difficult to fit a GCS onto a 30"x42" sheet in landscape orientation.
5. Allow us to "flex" individul schedule "columns" and "rows" once the GCS is placed on a sheet much like we can do with regular Revit Schedules. I like the "Grid Appearance" parameter for the setting of a default appearance for a schedule, but if I happen to need one column to be wide to accomodate a bit more information in a tag, i don't want to have to make every column location mark wider, only the single column that contains the extra information.
5. Allow us to show footings (for dowel information and footing tagging), connections (baseplates - cap plates), and framing members (diagonal braces...) in column schedules.
I'm sure others can chime in on some of their frustrations or ridiculous work-arounds they've been using to circumvent the shortcomings of Graphical column schedules. Personally my latest favorite has been to cut full building sections and vertical-break the sections down to just wide enough to show each column for tagging purposes (naming the section with the parallel grid line and showing the perpendicular grids in the section) in order to get a better context for the actual column conditions. This works well, but is still more of a headache than an improved GCS workflow could provide.