Andre Hotz has an improved mirror-weight script, among many other useful Skin tools. Some pretty awesome stuff in there, though Rob might start freaking out if he looks in the innards. (don't do it man!)
what do you mean "symmetry rigging is broken"? they changed something in biped which means that in Figure mode, you have to click the little black * icon button to create a new "Collection" before you can copy/paste opposite poses (which I think is what you mean by "symmetry rigging" ?)... once you do that, then all the…
I feel your pain also. Skin needs a rewrite, preferably by someone who has used it day in and day out for a few months. It works best if you do skin by the book and never screw up... ever. Even then you can't expect it to work like it should. The more you use it the less likely you are to do something it doesn't like.…