from a practical point of view I personally prefer to have all
    production files for one type of task in one directory rather than
    in 2

Indeed, I actually think it would be a great step if we could abandon
TDS with its harebrained(*) splitting by file format, and every package
simply be installed in /some/texmf/packagename-vvvv, as the author
creates it.  Then the whole ctan->tds conversion problem goes away,
updates become relatively simple, authors can do whatever crazy subdir
structure they want, etc.

(No, I'm not planning to change TL or anything else in this way. :)


(*) it was necessary back then, but I see no deep reason for it now.