Hi Yadin,
This thread relates to resource results, not featured collections or featured collection categories.
When looking at a collection's contents (i.e. results) they are always "as added" as you request, so I assume you're talking about catagories or when listing the collections themselves.
Within the next couple of months we're moving featured collections categories to use the same nodes table/structure we use now for fixed list metadata fields rather than the "theme1", "theme2" system we use now. This will make it much easier to manage featured collections and categories and will make it possible to manually order them too.
In the meantime there has been a hack in place for a while whereby you can prefix the names with an asterisk to move them to the top. Two asterisks given them extra high priority, and so on, so you can do some very crude ordering.
Dan