Setting up a puppet is a lot of work. Especially tweaking and fine-tuning all the specific parameters for head-wobble & tilt and wind on dangles, etc. It's not bad to set it up the first time, but once I've made those decisions, I want to know they're secure and easy to apply to other groups or puppets.
A keyboard shortcut to copy specific behaviors and the behavior settings from one group to another. Similar to Photoshop's Copy Layer Styles/Paste Layer Styles or MS-WORD's "format painter" which uses the keyboard shortcut CTRL+SHIFT+C to copy the font/style/size/color and paste that style onto another selection of words with CTRL+SHIFT+V.
This functionality would be especially useful when you have two groups that you wish to add cycle-layers to, or multiple hair-dangles you want to add all the dangle behaviors to. In my case, I had a multi-footed robot and needed identical cycle-layers on each of them. In the present CH, I had to get all the settings just right, take a screen shot of the settings, then set them all up again for the next group, and so on.
This would also be helpful when updating a puppet character from an old PSD to a new PSD. (e.g. copying the dangle settings from one puppet onto new hair pieces) Or it could also be applied from one puppet to another. (e.g. "Hey, I like how that head moves... copy the camera sensitivity, head-tilt, etc. onto my other puppet.")
And as long as I'm giving input, make it CTRL+SHIFT+C / V. :-)