Since we implemented
XWIKI-13060, whenever we create a wanted link in a page (such as [[test]] inside Test.WebHome for example), it'll create a sibling Nested Page (i.e. test.WebHome) instead of a children page (Test.test.WebHome).
This is a regression from the previous behavior and I don't think it feels natural that wanted links don't create children pages anymore.
Note: Reported on the list at http://markmail.org/message/ssswgb4hljf6qhbx