There are open source projects trying to recreate things like Stars!
Also, Shrapnel had a thread about "whats the next game you would like to see" and they have a fairly open-door policy.
I think Aaron has done a great job, but the talent represented by the crowd here is extensive. If they all jumped into a project I tihnk it would be great. I have some ideas for beating the "huge game" limitations and allowing for larger maps, more planets, planets whose appearance changes with game play, more nations, random nations, unique names, non-linear AI's, and majorly increased random events. All of those are items which tend to have to be cut back when they make the game too large to fit on a CD.
And of course Id love to see client and host seperated, with a host that will run on linux servers
Gandalf Parker