I don't think it would require a rework as such -- what I am saying is that ADPs are not valid XML files, that is all.  There might be a way (or there may be none) to shut off nXML's validation of @@'s.  If there is no way -- well, so be it.

The only benefit I see, is that if your template validates, then there is a greater chance that generated page would validate as well.  Otherwise -- see my old post (http://openacs.org/forums/message-view?message_id=118033) about how compliant OACS is (was? will check) with even basic requirements (like quoting of attribute values and absence of open-ended tags).

One really big advantage to moving to .adp's that validate as xml is that there are a number of bugs that are not diagnosed very well when the adp is malformed (eg an unclosed multiple tag produces a not very intuitive error). Having the adp's validate would make automated testing for that sort of error straightforward.

On the other hand, dreamweaver will work just fine even if they are not well formed xml (although maybe this has changed since version 4 which was the last time I worked with designers who used it).

I think it would be pretty straightforward to fix the most common things (singleton tags, attribute quoting, and case would be most of it), but <if> tags and the nesting of adp tags inside html tags (like on the body tag in the master template) would be problematic.

quoting everything and fixing case can be done w/o discussion, but we would have to have a TIP for the other required changes and while I would vote yes for such a change I am not sure other people would.