If you have a new site I can see it being worthwhile but if you're already PR4+ why bother, your not going to get much power.
I never thought of starting my directory on a dropped domain name. I do not think that PR is the only selling point for directories. I have worked from a PR0 to a 4 (and rising) with quality links. The reason why people submit to my paid directory is the good price and the amount of traffic it gets. I could care less about the PR, its all about the quality and traffic to me. I agree that you need to be careful submitting to paid directories, but there are some quality ones out there that plan on being around for some time.
I agree but it's mainly submitter ignorance. If a site is well trafficed and cached recently it means if you write a good unique description you may start getting uniques through it. No one ever mentions that; not sur why?
Its all these people starting directories thinking they can succeed, but have no knowledge of the industry or on how to successfully market a website or directory for that matter. They really screw the people that make paid directories and work their ass off promoting it!
PR is important to submitters, so as a directory owner, if you want to make money you have to be a little concerned too. The problem is that these scammers are buy a dropped domain and using the inflated (or non-existant) PR to sell featured links, site-wide links and then flip the directory to an unsuspecting owner so they don't have to deal with the fall-out of folks being angry when the PR5 goes down to a PR2 (or less). There is also the reasonable expectation when purchasing a website that has PR4 and higher that you will have to spend less time (and money) link building because the site will already have an established page rank.
Ok, well I do care a little about my PR, but not as much as my traffic and what links are getting into my directory. I think you still have to spend a large amount of time link building even if over a PR4 if you want to stay ahead!