Lightroom has a nice capability for stacking images that are closely related.  Usually this would be manual stacking for images that make up a panorama or HDR, but could also be stacks based on a burst of images.  A burst might be images created in automated focus shift or in an HDR or multiple exposure bracket.  LR has the ability to automatically create stacks for images created within a specific time interval.
It would be nice to have a similar capability in PM Plus.  Manual stacking is very important, and time based automated stacking would be nice.