We have a new and better version of the front-end server on the drawing board. Resources and external commitments will govern when we'll be able to do something real with it. Features should include greater flexibility, greater support for access/resource control, and easy support for Explain (possibly with Zebra as an extra database engine).
YAZ is a BER toolkit and as such should support all protocols out there based on that. We'd like to see running ILL applications. It shouldn't be that hard. Another thing that would be interesting is LDAP. Maybe a generic framework for doing IR using both LDAP and Z39.50 transparently.
The SOAP implementation is incomplete. In the future we hope to add more features to it. Perhaps make a WSDL/XML Schema compiler. The authors of libxml2 are already working on XML Schema / RelaxNG compilers so this may not be too hard.
It would be neat to have a proper module mechanism for the Generic Frontend Server so that backend would be dynamically loaded (as shared objects / DLLs).
Other than that, YAZ generally moves in the directions which appear to make the most people happy (including ourselves, as prime users of the software). If there's something you'd like to see in here, then drop us a note and let's see what we can come up with.