There is QT_QSETTINGS_ALWAYS_CASE_SENSITIVE_AND_FORGET_ORIGINAL_KEY_ORDER macro in qsettings_p.h which decides which is used to tell how it should function on a platform. Maybe this could be broken up into separate settings and made available through API.

For example if an .ini file is moved from Windows to Linux, an application might not be able to find all values because it is now read case sensitively.

Key order preservation behind a separate toggle wouldn't hurt either.