I use facelet components heavily based on ideas from http://www.ibm.com/developerworks/java/library/j-facelets/

I find that they make it much easier to design facelet pages and maintain them. I would have like to see them used by seam-gen but have been told that JBoss tools currently does not do tag completion or good visual rendering.

It would be wonderful if there was a way to get tag completion and better visual rendering for facelet components even if I had to create XSD files etc for each of my facelet components.

I discussed it in the comments at http://in.relation.to/Bloggers/ItsTimeForFaceletsToStartUsingXSD
and was asked to report it in JIRA.