One of the most important features of all these tools is the rotation. Such a tool is only really useful if I can rotate the new mask from keyframe to keyframe. At the moment, I'd have to manually zoom in or out on each handle if the perspective changed.
I got the idea (probably wrong, given my incompetence) that to make rotations or other changes on the mask, the compositing engine of Cinelerra is not suitable. A completely new compositing engine would be needed to create matte on separate and independent alpha channels. That's why in an old email I asked if it was possible to integrate OpenFX, which would allow you to use a real rotoscoping tool, with all the features required by you and me in the ticket 02 of MantisBT. But I don't think it's possible: at least it means building a new compositing engine or completely changing what's already there.