I'd like to see better animation tools. Tangents for splines, better graph editor. IK turned on and off during animation. Possibility to select any bodypart for IK.
IK which doesn't twist the figure in all kinds of painful poses.
Implement Bullet Physics (the SDK is free under FreeBSD license) or Physx (from NVidia also free).
Better styling options for dynamic hair (look at Carrara for example, where you can pull guidehairs mid way). Paint zones instead of selecting polygons to better control the shape of the zones.
Change parenting during animation. Animation:Master can do this.
Real subsurface scattering (a tool which is specialised in human models should have this right?)
Muscle tool (blender has it, look at blenrig http://www.jpbouza.com.ar/ESP2/descargas/blenrig-3/id/en).
Ragdoll physics where you can specify the ending pose.
Moveable pivot point during animation.
Walkdesigner for 4 legged creatures.

Ability to add tags to items in the library for a more powerful search. Ability to reorder things directly in the runtime, rename folders, etc.