I know you will argue this point but your users are in fact webmasters. without their submissions the directory would grow much slower indeed. if at all.
I think, truly, you have very little understanding of how the cogs within DMOZ turn and this could be a general problem here and webmaster world throughout. The submission pool is the smallest of the sources available to editors. Most (and yes I truly mean most) of the listing are made by editors who physically search the net for quality sites. The reason they do that is the ration of good/bad sites is far more favourable when looking yourself. In other words the submission pool is that full of rubbish that it takes to long to find a 'gem'.
I will tell you now, in all honesty, there is a huge gatering of editors who would cheer very loudly if submission where completely turned off - never to return..... dissapear into yonder. It has been discussed however the only reason it was not turned off was simply because we may missing out on that 'one quality site' that we would not have found otherwise.
Many editors don't even look at the submission pool - they did not join to look at them and looking at them is not a condition of being an editor. Whether they add sites from the submission pool, the local newspaper, the back of a bus, and advert on the telly or searching on the net then that is all fine. But truthfully every other source is more reliable and provides better results that the submission pool.
I can see why on the outside submissions seem important and it can be hard to actually see how we get all of our links but submission really do play a small part in the growth - and that is a fact.
This could more than easily be dealt with by the same set of scripts. if a site has been declined then simply block it from resubmission for a suitable period. or have a script check it to see if its been rewritten (compare reviewed with new) combined with an enforced delay period it would stop such abuse.
I see what you are saying but the human factor is very very important. A script cannot tell if the content has changed etc etc and we would never trust a script to make such decisions.
If the ban period is set high enough say six months, that would make all webmasters think twice about abusing the system.
Again it is the human factor. Okay, many editors would like to punish the webmasters who abuse the directory, but in the true spirit of ODP it is not something that helps anyone. Next month the domain could be taken over, sold on, changed content etc etc and as such if listing it would help the user then we are happy. Not listing it under a ban would have gone against our beliefs.
I can see what you are saying and I am sure that some scripts of some sort could be used (infact some are but that internal and I won't go into that) but many of them have been discussed and considered and ruled out for very valid reasons but mainly coming back to the sole purpose of the directory.