thanks for the overview of history. That clarifies things a lot!
> so to answer what to focus on: i'd say expl3 playing with it and joining a
> discussion of streng and weekness (yes you started that already with our
> other question) and to look at the explerimental packages only from their
> implemented functionality (eg the template interface) but not from their
> internal implementation
I understand. Thanks a lot for these hints. This
is very useful in the reading process, especially
to understand the relation between things.
Good luck with all conversions btw!
As for expl3, could it be an idea to take some source of a
latex.exe (for instance from MiKTeX for windows people) and
change the kernel being run into l3basics (+additional) so
that it is easier to develop the kernel itself and we don't
have to worry about the existence of the LaTeX2e kernel
anymore. This would take some effort, but might be helpfull
in the end. It's just an idea (and I guess that some of you
must have thought about this as well in the past, so if this
would engage an ancient discussion, please tell me that the
idea is old and not workable as to save some time :) )