The helper bones are necessary (for me anyway) when I'm making a conforming dress or skirt. Hmm, what I may do is just what I've been doing and include a seperate object file for the dynamic dress. I like to try to get my models to sit occassionally, but most of V4's clothes were clearly intended for her to be walking or standing.

Getting conforming clothing to bend right for sitting or kneeling is a PITA. This is made worse by V4's default bending. 
I agree with you on the extra bones as they help some. 

WARK!

Thus Spoketh Winterclaw: a blog about a Winterclaw who speaks from time to time.

 

(using Poser Pro 2014 SR3, on 64 bit Win 7, poser units are inches.)