I believe that the new versions of plugins that have not too long after they should turn off the ability to download them. There are plugins of 2011 that certainly need to be revised to update to the new wordpress.

There are duplication of plugins, plugin with support ticket unanswered for months, plugin without screenshot or faq!

Many plugin have the same problem: load in the head of the all page the css or js even if there are. The optimization and the cache with this plugins it's a stupid and annoying problem -.-'