For what its worth, I had similar issues yesterday (some related, some not related) but I was watching the debug logs and without debugging enabled, you think the process is 'hung'.
The dialog just shows 'connecting' or 'reading', but with debugging on, you actually see that it IS doing something, in my case, it was reading through every single thumbnail and image verifying existence BEFORE starting to download (or changing from connecting or reading).
Perhaps something in the new plugin that is checking what to download prior to actually doing it. Subsequent 'updates' are faster now.
Can someone enable debug and see if you are seeing the same thing?