I'm loving the Desktop Mail feel to the new Writer, I use writer all the time, and it looks like it's just gonna get better. I can see certain things that might put them back a bit just from that screenshot:

The bar at the top (Publish, new etc...) doesnt have the rounded corners like the Desktop Mail client has, maybe theyre still working on the UI.

Also the pane on the right still doesn't seem coloured right, plus I'm guessing that new Spaces Video insert feature will be added to the 'Insert list', thats probably taking some time to integrate...

Now, going off on a limb, I would hope that maybe some extra special Spaces integration is coming and thats also taking time...Microsoft needs to promote Spaces more than all the other sites that Writer works with, maybe we would be able to actually edit the Space's layout and design etc, just like we can in IE or Firefox, in the Writer Client in future...

Josh