It is not just the number of editors. Editors choose what they do, and they naturally choose sites that are more important to surfers (guaged, of course, by their own estimate of importance.)
The thousandth widget maker doesn't add much to the directory at all, but the first Methodist Church in Lower East Podunk, New Jersey; or the only symphony orchestra in southern North Dakota; or the second book-length biography of Abraham Lincoln; or ... you know, really unique sites ... are more important.
This means that overcrowded categories tend to be neglected. The result, for users, is improved coverage, greater comprehensiveness, and more information available more quickly. The result for commercial webmasters needing quick website promotion is ... not a concern.
The usual advice applies. If your service has any kind of local flavor -- then make sure the website mentions that, and also submit to the ODP Locality category. (The third widget maker in Lower East Podunk NJ gets a LOT more attention than the thousandth one in the universe.)
But that still is no guarantee of instant review. If you need instant commercial promotion, seek it from someone who sells it -- there are numerous such sites. And remember, your site won't be listed in the ODP because its promotional campaign wouldn't be complete without an ODP listing; it will be listed because it is so important that the ODP could not be considered complete without it. (In practice, somehow the odds are probably that the day you say, "I don't need an ODP listing; people are coming to me from all over the world already", some editor will come from across the world to review and list the site.)
