I understand. We definitely want C++14 features first :) But it seems like some of the problems would be easy to fix. Like - istream_iterator is defined in <iterator>, so <iterator> needs to include <istream>, which has a huge subtree. Iterators are a much more "leaf" idea than input streams. Why doesn't <istream> include <iterator> instead?

Or, <algorithm> gets most of its subtree via <memory>, which it needs for a few algorithms that use temporary buffers. That one is beyond your control... The standard should add an <algorithm_lightweight> header containing only algorithms that don't need extra memory. Or you could add your own such header to use internally.