Patrice, Gavin - I've been talking with my friend Norbert Preining, who used to be the Debian maintainer of the texlive packages. (He's also one of the principal maintainers, with me and a couple others, of upstream TeX Live.)
He confirms that cm-super is not installed as part of the "recommended" TeX packages. It's 60+mb and that just seemed too big. It's been that way since 2005 or so and no one has complained. Which surprises me, but I guess relatively few people use TeX, and relatively few of those would be cognizant of bitmap vs. outline fonts, and those who are, just install what's needed. cm-super-minimal includes only the 10pt ("1000") fonts. That's something, but not enough for any nontrivial LaTeX document. He's willing in principle to suggest that cm-super[-minimal] become part of the recommended TeX packages, but I'm not sure that is warranted. If nothing changes, I guess the implication is that microtype should not be used by default, since the fonts in Debian will not be scalable. (No idea what other distros do, but Debian is probably enough to be a stopper.) If you want any action to be taken, let me know. --thanks, karl. P.S. I certainly understand not bothering to individually configure each \usepackage line as I mentioned in passing before, but I surmise it would be useful to have a way for users to say "replace the entire default preamble with this string". Even including the \documentclass. Since there are a zillion ways to do any particular job in LaTeX, seems useful to provide a general way to support "ok, if you want to choose all the packages yourself, you can".