i said, re tugboat,
    in pre-latex days, it was often possible to run
    the camera-ready copy of an issue as a unit.  no more.

and david responded
    No doubt true if you say so, but is LaTeX the cause or is it more that
    in those days you were not trying to typeset an article in cyrillic
    followed by an article about 16bit Omega fonts followed by ..

it's some of each.  if article 1 had to redefine the output routine
to enable side-insertion of figures, there was a good chance that
article 2 would have to be started up separately.  but cyrillic (at
least using the amsfonts and associated font-handling) would not pose
a problem, nor would, usually, any article that took care not to
redefine "core" or primitive control sequences or reset penalties.
actually, reset penalties can be even more insidious than redefined
control sequences -- the latter often kindly crash and make their
presence known, while the former simply cause different line and
page breaks without any "obvious" reason.

me:
    that little matter of incompatible packages is a real beast.

david:
    Yes for you especially in TUGBOAT I suspect that you are always going
    to be hitting some real hard incompatibility, but as I said to
    Sebastian earlier in this thread ``you don't count'':-)

it's nice (?) to be a member of that exclusive minority ...

but i agree that, since one of the purposes of tugboat is to show off
what tex is capable of, the boundaries are going to be stretched quite
regularly.  at least (most of) the reasons for problems are more
tolerable now than in the days when a single page had to be set in
four pieces and patched together with tape because of limited memory.

regarding the use of multiple (possibly incompatible) packages,
    In these cases you can usually (perhaps:-) arrange just to load all
    packages used by any of the sub documents at the start of the `master'
    document and then just input each sub document in turn (after suitably
    disabling all the preamble commands).

i would surely welcome your input toward resolving this dilemma,
and i think that robin probably would too.
                                                -- bb