I successfully downloaded and installed the VSE Transform tool add-on found at https://github.com/kgeogeo/VSE_Transform_Tools into my blender. Through the add-on, I'm able to click on the VSE viewport and move and edit things like images and movies around straight from inside it. The add-on actually works great, except for the way it works with keyframes.
To save any of my changes, I'm required to manually insert the keyframes. Automatic keyframing does not work. For example, if I create a keying set, add the location positioning properties of a transform strip to that new keying set, insert a keyframe, change the frame I'm on, and try to change location positioning through the add-on, no new keyframe is inserted even with automatic keyframing enabled.
The only way I seem to be able to keep any changes made is to manually insert a keyframe myself. In the same example, if I use manual keyframe insertion at the end, the changes keep.
I would like to note that the add-on actually came with its own additional way of inserting keyframes without a keying set, accessed by moving the mouse pointer over the VSE viewport and pressing the I key. Inserting a keyframe through this secondary method does not immediately show a new keyframe in either the dope sheet editor or the graph editor. The add-on appears to wait on inserting a keyframe until blender takes one more additional action (changing selection, changing frame, etc.). I feel as though this somehow might help explain why automatic keyframing doesn't work natively with it.