The idea of the merciless refactor is to be extremely thorough in cutting apart a topic and separating it into multiple subtopics or otherwise "cleaning off the Cruft" This process is absolutely essential for an older Wiki. Often, a page will appear to be mature to a regular, and to new users will appear unapproachable, however the process of disregarding social ties (ownership) to a page and flesh it out is of extraordinary value.
Essentially, pages get out of date because authors begin to become more and more intimidated at making major changes and "stepping on toes". Bold authors who pick apart elderly pages to update them are of great use to a topic, and are essential for keeping pages tidy and up-to-date.
Some wikis have the concept of "being bold", which is something like being merciless.