Folders and groups are the same concept—as the already existing "Pre-comp". The thought behind the "Pre-comp" is to “group” a set of layers. Rather than reinventing the wheel and making After Effects more complicated with added new features like groups and folders, we can improve the functionality of the "Pre-comp".
Here is a demonstration of how that would work:
https://vimeo.com/137312858Suggested Shortcuts:
/ = Split Timeline to show pre-comp. Only works when comps are selected.