The following would be nice features to ease the tedium of defining large permission groups:

1) Add a button to copy an existing section to create a new section within a permission group. Then we would just need to provide the name for the new section instead of selecting all the individual permissions as well.
2) Add the ability to append a group to another group. For instance, say we have a main group which contains 40 sections and a supplemental group with 10 sections. If we could just append the 10-section group to the bottom of the 40-section group, then we could just quickly give new names to sections 41-50 in the new combined group. The 10-section group could then be used as a template which we append to various other groups as needed, instead of having to individually go in and add 10 new sections to every project which needs them.