I am not a DMOZ editor. But if I had the time to be a DMOZ editor I would be committed to ensure to list all relevant websites in a specific sub category and make sure it is:
1. up to date
2. does not contain URLs of websites that are not good (anymore), spammy, have been sold or do contain a parking page
3. errors are corrected in time
4. the most popular websites (e.g. by internet stats) are not missing
5. the categories are correct (e.g. language of the website, target audience or audience by internet stats etc..)
I think as a DMOZ editor I would primarily add websites myself after doing a research...as this is probably the quickest way to do.
I would try to stay as neutral as possible. I would not even care about how "spammy" URLs are suggested to several caregiry by webmasters that might be a bit angry as they were waiting for a long time. This could also be abused anyone. Imagine you know someone is submiiting a website, you could suggest it to thousand other categories and DMOZ editors would think " we will not list him if he is spamming".
I think DMOZ editors should start in a small category. If they do a good job they should be allowed to move up the ranks and edit more.
If they they fail to keep their category clean/up to date, they should be warned an finally banned. This way, all categories would be clean, up-to-date and reflect the current state of the internet better.
I have seen many DMOZ categories with missing websites that are quite big and popular and definitely worth to be listed...independent of the personal opinion of the editor.
I would also think about the people and not by personal opinion when adding websites. If I think others should see/know this website even if I do not like this website for personal reasons, I would add it without a question.
If it would be done this way, nobody could come up with excuses like "we don't mind/care that some categories are outdated and have not been edited for 2 years as it is up to the DMOZ editors and if they don't do it, they don't do it.".
A DMOZ category that has not been edited for a long time or has a long queue should get new editors and old editors should be kicked for not doing their job. It is a voluntary organization, but this does not mean being lazy should be accepted.
If categories lag behind and are unedited, this means too many editors are responsible for too many top-level categories.
I think DMOZ needs less editors with high editing powers and more editors are the bottom of the "pyramid".
I think anyone that can find 5 websites that are missing in a category or 5 outdated links, should automatically become the new editor and the old one should be kicked.