I have also noticed that you are no longer allowed to drag multiple emails to a Zimlet. Under 6 we had Downloader installed and lots of people would use it to archive off groups of old emails. But since the upgrade to 7.0 you can only drag one email at a time.
I think the Zimlet API has changed.
Also I think the Online Gallery should allow you to filter the Zimlets available depending upon your system.
