My research team (Sign Language Synthesis and Interaction group: http://slsi.dfki.de) just released an addon to simplify multiple F-Curves at once, which also temporally aligns the retained keyframes.
You can find a release note, together with links to the addon and a manual, at the following link:
Hope you can take advantage of it.
Fabrizio Nunnari & Alexis Heloir
What’s the process to follow to have it (eventually) distributed with Blender official releases?