By default, the first view of a surname index page lists 1,000 names. For example, see:
http://www.wikitree.com/genealogy/WILLIAMS
When a page is resorted, certain things about it change, and the Wiki Genealogist Tools appear. When this is done, we could have it list 500 names instead of 1,000. That would be better for the merging and matches options, especially. The Javascript can have loading problems on certain systems with 1,000 names.
Would anyone care? Is there a reason you'd like to see 1,000 names when you sort by first name or birth date? You could still select that as an option, but we'd be changing how it automatically displays.