We are not planning to add faux 3D graphs, like 3D bar graphs. These graphs can be misleading because it can be difficult to compare the bar heights and bars can be hidden by other bars. Stacked bars are sometimes a better options or use a split axis.
Though not strictly 3-D, the Scalar field command allows you to represent a third dimension (e.g., a surface plot). We have been developing this command for a while and it does some pretty interesting plots. We would be happy to have users test it out before we add it to the release.
We just added some examples here: Scalar field
If there is something else you have in mind, feel free to send a screen shot of what you would like to see.