There are several issues with this component, including:

need clear justification for use cases in which http://www.php.net/parse_url is not a better choice than using this component

e.g. use cases for URI's, not URL's

e.g. construction of URL's is not supported by parse_url()

code require()'s bulky subclasses (even though they might never be used in the request)

Zend_Uri should not be an abstract class:

http://www.w3.org/TR/uri-clarification/

http://www.ietf.org/rfc/rfc2396.txt / http://www.faqs.org/rfcs/rfc2396.html

Zend_Uri should work "out of the box" according to the RFCs above

Specialized handling of schemes should be provided by scheme-specific subclasses that are not require()'d to use Zend_Uri.

A proposal is clearly needed. A rewrite might also be needed, but not before a proposal has been written that lists the purpose, use cases, etc. I am happy to help, just IM/email me anytime.