I agree very much with this — in particular, where you're pre-filling a NEW collection that I don't currently have. At the very least, if you're going to suggest collections, make it obvious that it's a suggestion.
Switching from a Google Account to a different sign-in option is a related, important feature.
Another use case: RSS feeds from our paid Basecamp service!
This appears to have been fixed in V.17
This seems to be fixed in V.17!
Yes, please... I can do this from the Google Reader 'Trends' screen, and it's very useful in pruning inactive feeds from my list.