I often find that the weights of my joints in a mesh-setup influens areas of the mesh, where it should not. Tweeking it, can be quite painfull since I often move the problem to another bone, so the problem is a lack of control of where the bones influence end up on the mesh. It would be nice to have a paint weight feature, so I can pick a bone and paint the area of influence. A good refference here is Autodesk mayas paint weights tool.

Maya paint weight tool demonstration:

Keep up the good work!