Not quite related to this particular release, but I kind of wish sync for extension data wasn't Opt-In.

Having to hunt down the option to turn on Sync for each extension explicitly and not even having that option for some extensions makes for a rather poor user experience.

Also, as someone who customizes the browser layout rather extensively, I'd like to see layout settings included in Sync as well (which toolbars are visible/how buttons are organized on toolbars/etc).