There have been discussions about what are the minimum requirements for Drupal to still be considered Drupal. Some have argued that it must include the entire core distribution.
I have argued that distribution profile builders require more freedom to re-mix Drupal.
Requirements
1) All include files
2) Must be compatible with all core Drupal APIs.
3) All required modules
4) All core theme engines
5) Drupal core licenses must be included
6) A working theme
Not-required
-All modules that are not required such as page, story, watchdog in Drupal 6.
-Core themes shipped with the default distribution
Edit away.