Fedora considers curl-minimal

There is a limit to practicality. Some considerations:

* Providing both curl and curl-mini variants may reduce the container by 100KB, but now you have added at least 500KB to your mirrors.
* Some software has so many build dependencies that, indeed, it may make sense to build a -mini variant and then another standard variant. openSUSE does that to a few select packages to cut down on overall project build time and/or reducing build cycle lengths. libcurl is not among those, because it is not nearly as dependency-heavy as e.g. systemd.
* xkcd.com/1172
* The overhead of ELF is so damn high these days. ~14 KB for an "int main(){}" built with standard compilers and options plus strip. Splitting libcurl into multiple component libraries hence raises the disk usage for at least one case. Your RPM/DEB database would have to process more entries perhaps (because now libcurl4 and libcurl-gopher4). ld-linux.so would have to deal with more libraries, load times getting worse. You really don't want to end up like samba-libs either, do you!?
* I predict that most people will probably end up with the full curl installed for one reason or another, and the security argument gets weak.
* The "url" implementation of many a browser has probably a lot more fat than curl. If only firefox and chromium would use libcurl instead of handstrung solutions, that might, overall, be a better outcome. Don't try to make the small smaller, make the large smaller.