My first issue filed against
Views VDC! :-)
#1812866: Rebuild the server side AJAX API introduced a new server-side API for Ajax commands that plays nicer with the new Kernel/Request/Response pipeline. The change notice is at http://drupal.org/node/1843212
The Views commands in views/includes/ajax.inc need to be updated for the new API, and possibly refactored in the process. (I defer to the Views team on that front.)
I didn't see an existing issue where this would be relevant, but if I missed one feel free to consolidate.