I think it's a bit unfair to suggest that all jQuery plugins have problems (I use the validation plugin and it is excellent for catching mistakes before a user submits a form and starts the backend processing). I see them as being in the same boat as WordPress plugins - there are some which are well maintained and up to date, and then a huge pile of others which were quickly hacked together and then never looked at again.

It's the same with CPAN, PEAR and anything else where you allow users to contribute additional separate components which aren't maintained by the core developers.