A short list of some of the features.

Please contribute to working on this list! Shape text: .. Currently only centered in the shape. ..* Boundaries can be easily exceeded. ..* No justification. ..* Single line only - no auto-wrap.

• Multiple element select. ..* With click-drag selection rectangle. ..* Scrollbars for canvas - currently you drag the canvas to move it.
• Zoom.
• Shape rotation.
• Custom defined connection points. ..* Including on connectors.
• Adjust custom connection points intelligently when shape is resized.
• True dynamic connectors.
• Other line caps besides an arrow.
• Ruler margins / page boundaries.
• Snap shapes to centers and edges.
• Printing (more or less easily implemented, actually) If you want to print, save the diagram as a PNG and use some other tool!
• True drag-from-toolbox-onto-surface.
• Arrow cursors for grip dragging.
• Undo/redo. That'll be fun!
• Better property UX - PropertyGrid's are ok for developers, they are awful for users.