Chris, you can still add your ancestors manually. Most web sites that attempt a world tree get bogged down with multiple duplicates which nearly defeats the purpose of having a worldwide tree. The same thing was happening on WikiTree and it is taking a lot of extra work by volunteers to merge and clean these profiles. Probably many of your ancestors in deep history are already on the site. It is the WikiTree goal to have only one profile per person and this seems the best way to proceed.
It means extra work to enter each individual manually, but makes for greater efficiency in the long run. Remember, you're not alone. All of us are doing the same thing--entering older ancestors manually. Not only are we able to check for duplicates one at a time, but this also enables us to verify documentation for each ancestor to make sure the line is correct.
To see the GEDCOM FAQ, click the following link: http://www.wikitree.com/wiki/GEDCOM_FAQ