Excelent new animation and rigging features may come to Blender with Durian. Read it for yourself:
* Alternative to quaternions for bone rotations. Eulers are already there, customizable Euler rotation order, axis-angle support and per axis locking are important as well. * Support of these same things, quaternions and the things mentioned above for Objects. * Animating the camera position and rotation by doing real life recording would be an interesting feature to have. Motion tracking would be needed for this, completely using open source tools of course, and the libmv project is a promising candidate. This would not be natively integrated, but use a script most likely. * Proxies will need to be improved, for example to support multiple instances of a character with variations.
* Preserve angles > 180° throughout the animation system. This may not be practically feasible to do it completely, mainly what would be good support is preserving this for constraints, and to avoid flips for dual quaternion deformation. Quaternions go up to 360° which would be enough. The idea is simple, implementation is complex, but considered important. * Spline IK. This in fact has very little to do with IK, quite the opposite, it's an FK method. It is a constraint to let n bones align with a curve. In this way it can work like the IK constraint, affecting multiple bones. There should be an option to have the bones stretch to fit, or to keep their length and possibly not reach or go beyond the edge of the curve. * Option for bones to have the bone translation values in armature rather than bone space for posing. This would be useful to present more intuitive values and animation curves to the animator, so that e.g. moving an IK target for a hand up will work with only a Z axis curve. This could be taking further with full local spaces for armature and bone rotations and translations, but for now an option to have translation in armature space seems sufficient. * Creating own animateable properties per bones, and display them to the animator. * Better support for scripting rigs. E.g. when animator selects a bone, hide or show some things, or when switching IK/FK, doing some operation, etc. Preferably not as a space handler type thing, but integrated and distributed with the rig. * Fix curve twisting problem by propagating frames.
Even more Aligorith has an idea that animation path will be tweakeble by brush (combed animpaths in 3d view :-)!