Google’s JohnMu helps frame the situation for us. Writing in Google Groups he said;
“ I wouldn't necessarily assume that we're devaluing Yahoo's links, I just think it's not one of the things we really need to recommend. If people think that a directory is going to bring them lots of visitors (I had a visitor from the DMOZ once), then it's obviously fine to get listed there. It's not something that people have to do though :-).”
Does the directory reject urls? If every url passes a review, the directory gets closer to just a list of links or a free-for-all link site.
What is the quality of urls in the directory? Suppose a site rejects 25% of submissions, but the urls that are accepted/listed are still quite low-quality or spammy. That doesn't speak well to the quality of the directory.
If there is a fee, what's the purpose of the fee? For a high-quality directory, the fee is primarily for the time/effort for someone to do a genuine evaluation of a url or site.