*"Please tell me in what way weightmapping would help me creating more realistic joints."*

weight mapping is a massive improvement. we arent seeing it used to its full potential yet because there arent any figures out that have topology modeled from the ground up to take full advantage of it.

before the latest Poser was released i was working on enhancing my earlier characters joints with dozens of JCMs.   i can tell you that with weight mapping the end result is much easier to accomplish in a fraction of the time.