Zend_Paginator should offer setDefaultItemCountPerPage().
Scenario:
Someone is using Zend_Paginator in his project and suddenly realizes that he don't want default 10 items per page, but he didn't use $paginator->setDefaultItemCountPerPage(10) - so he can't use replace.
How it should work:
Zend_Paginator::setDefaultItemCountPerPage(int $count); //would change from 10 to $count
Resolved in revision 16141 and merged to branch in revision 16142.