You're not new to genealogy, yet even you are struggling a bit with the concept of lines
Marco I am not struggling with the concept of lines.
I understand all that I need to know about them, and the Ahentafel that is presently devised and has been used by genealogists for over 200 years works just fine for me.
I think energy would better be spent on things that are somewhat likely to be implemented and I am not convinced that the concepts being discussed here in this thread and the "Lines Pairing System" discussed in another thread will ever be implemented in FTM.
Some of the other ideas, such as "Cousin Free" register reports, [that have been discussed elsewhere] are probably more likely to be implemented