Sorry, we rarely visit the beta forum anymore since we aren't in beta. :)
If you are still using a beta version you might want to up to the newest version by going to http://download.live.com
The new forum can be found at: http://social.microsoft.com/Forums/en-US/writergeneral/threads
And to answer your questions:
0) We are looking at possible improvements to the tab/blockquote feature, but one of them is not to use a <div>
1) We update Windows Live Writer with the Windows Live Essentials suite which in the past has been roughly on a one year schedule.
2) We have a blog at http://windowslivewriter.spaces.live.com/default.aspx?wa=wsignin1.0&sa=433950094 where we usually post when a new version is out.
3) Posting suggestions on the forum I linked to will make them visible to me and the rest of the team. Or you can email us directly at wlw-team@microsoft.com
Sorry for not seeing your post earlier.
-Brandon Turner [MSFT]