Being that you know more about Commotion than anyone, and because Commotion is dead, is there anything that YOU would buy if you didn't have Commotion? That is, what software is out there Windows) that has all the bells and whistles of Commotion? If there is nothing, what comes closest?
Silhouette roto is the king roto tool these days. I would recommend working with this plug-in for roto along-side After Effects for compositing. Other good compositors include Digital Fusion, Nuke, or Combustion.
Curious gFx was a compelling competitor, but was gobbled up by Adobe. This could potentially be another big player.