It was a great idea when it was created, but over time the landscape of the web changed. DMOZ was founded before Wikipedia and even Google, back in the days that finding stuff was *hard*. DMOZ editors would curate lists of sites that would give a good overview of the topic, but it turns out that Wikipedia's approach to topic curation was better in the long run (and I think that many DMOZ editors are also Wikipedia editors). Directories also died a death as search engines got better, and in the end DMOZ was only really important for SEO purposes.
A long outage at the end of 2006 didn't help at all, and many editors didn't come back after that. Every time I log in I am horrified at the enormous backlog of submissions. For a long time, DMOZ was a great and useful resource. I don't think it has been the case for a while though, but the data it curated is still of value and it would be good if it could be preserved somehow.