One thing to remember is that Poser can handel both legacy rigging (falloff zones) and weight mapping, and it seems, for some reason, they have elected to leave both types available in their figures. So. for instance. Miki 4 has both falloff zones AND weightmapping in it;s cr2, altho the weightmapping is the only one checked as active. 

When transfering rigging Poser transfers both the legacy and weightmapping. One of the first things I do in clothing is merg the legacy mapping to weightmapping, then I massage the combined weight mapping weight mapping... well I'm lieing a bit since any more I tend to just paint my oen mapping from scratch but I started out massaging the transfered.

Another thing to learn is the bulge mapping. With some careful editing these can take the place of many magnets and JCMs altho I thing in some cases JCMs are easier, especially with either Zbrush (Goz) or colorcurvature's PoserMorphLoader.

One other tip, When working the weightmapping you need to check ALL of the affected actors since some actions are accululative. In other words say you adjust the abdomen weight mapping to suit your figure, you also have to be aware of how the chest and hip weight mapping will affect the same areas. They can often cause odd mistakes. This is one of the main reasons I started painting from scratch. It;s more work but more accurate.

I'm not sure why SM elected to keep the legacy stuff in their new figures, maybe they were just unsure of how well their weight mapping would work, or the riggers weren;t as familiar with what the engineers had built. Still, as has been said, weightmapping is definately the right thing to learn, it has a lot of power that has barely been touched so far.  For instance look ar the SM video on thier Dregon and lsiten for the phrase "Skinning Method" (also foound in the 'Figure' Drop down menu... This seems to be an area almost totally unexplored.