I have only recently started getting into the SE network of sites. As a new user it was a little confusing that I had to create a new account for each site, as I would have imagined that these would be combined into one account. I now understand why, Open ID requires new authorization for each site so it is out of SE's control.
The SE drop box on the top left corner is nice, but is it possible to get a feed of information about activity, my own and others, from all the SE sites which I am a member of in one area.
I know this will probably sound similar to this question, Create one page on SE to show my notifications for all SE, etc sites, but instead of only getting a feed of network wide replies I think it would be good to get a feed of information from each site that I have an account, all consolidated into one overall feed on the SE website. This way I could view the interesting, featured and hot feeds of multiple sites at one time. For example I could see SO and Tex questions together.
"But you can already view multiple site feeds at once by choosing sites in the right hand side of the SE page!!" Yes, that is true. I couple of problems with this: I have to manually select the sites (not a big deal, but automatic select of the sites that you are a member seems like a smart option). It is also displayed in a different style to the feeds in the full sites, there is no way to switch between the interesting or month viewing modes etc.
The other area of improvement is the User page, which again could consolidate statistics, activity, favourites etc into one place. This is very similar to the suggestions in the previous question that was linked above, but it is something that I think would be a very useful feature, which would still benefit from more discussion.