Moving XML processing to the client

XSLT only in IE 5.x+MSXML 3.x Using XSLT on a browser pretty much requires Internet Explorer 5.x plus a separate install of the latest version of the Microsoft XML parser. There aren't a lot of users with that configuration except XML developers. Mozilla has some (growing) XSLT support, but it remains to be seen...
DOM-processing environment conflicts Internet Explorer both subsets and supersets the W3C DOM, making compatibility with the much more DOM-compliant Mozilla browser difficult.
No common means of specifying non-style sheet transforms The only transforms available generally in browsers use XSLT, not things like SAX filters.
No common means of integrating scripting and XML While there are HTML-based workarounds for putting scripts into XML documents, they are non-standard and not exactly favored by large segments of the XML community.