I think, it would be nice, if the complete milestones could be shown under the WIP milestones, because newbies want to know, whats done in Milestone 0.1, 0.2, etc. when you are at milestone 0.6 xD
Maybe in 0.6 I will add a "Show All" link to the roadmap page.
There are now links on the Roadmap page to view all, completed or uncompleted milestones.
I like the right boxes :D