How about adding the capability within the Text/Graphihcs edit window to do freehand drawing on video frame using a pen with settable propertiesmminimally including size, color, and alpha. One can approximate freehand drawing using the Polyline objects, but is limited to strictly linear segments and sharp connecting angles. A freehand drawing tool would do much to extend graphic overlay capabilities.
This would seem pretty readible doable if implemented simply, for example, by treating each continuous freehand "swipe" as a separate graphic overlal layer, just as is done with the other graphics objects (line, ellipse, etc.). Each such "swipe" could then be similarly accessed to modify, move, erase, delete, etc. like any other of the several objects that might be overlaid (e. g., Line1, Ellipse, Polygon, Line2,...) on a video.