What we are lacking:
First, I would love to see Scratch redone in a faster environment than Squeak. While you can do some pretty good movies and games, an empty loop of 100 iterations takes over 4 seconds on my reasonably fast laptop.
Second, I still would like to see Scratch with plugins. This would allow me to abstract some complex code into a brick that the children could use. This would also make it nice to not clutter up the default code space.
Now that I've started down this path, teachers are asking me for programs typically reserved for college students, but simplified for elementary students. Specifically, they've asked for a spreadsheet for kids that would allow them enter in data values and create graphs. So far, I haven't found anything too helpful.