The intention of the CoFH Common Library is to establish a framework for modders to use to avoid "reinventing the wheel," as it were. This library contains a lot of basic functionality that quite a few mods end up adding at some point during their development.
Ideally, using this library will allow for more rapid mod development as a lot of the "boring" yet essential code is provided here. Additionally, it has the potential to greatly reduce permgen space, and who can argue with that?
Obviously, we have to maintain this library and keep it compatible with the changes and updates introduced by Minecraft and Forge, but we'll try and only add new things if at all possible.
If you feel that there is anything obvious or very basic that we have missed, feel free to suggest it to the team.
We look forward to seeing what the community does with this.
Oh, and don't be a jerk.