I spent the day visiting Alberto Conti at Northrup Grumman today. NG is building JWST. I got to see it being assembled in the (huge) clean room. I also saw a full-scale model of the sun shade that they use for testing deployment. It is just straight-up absolutely enormous!
The point of the visit was to learn about NG's new proposals and concepts for NASA-funded astrophysics missions. I learned that distant, formation-flying star shades are actually practicable, especially at L2, and that ground-based testing is extremely promising. The reason the formation-flying is possible is that L2 is very flat, gravitationally. That said, it does take days or weeks to switch the pointing of the "telescope", which consists of two spacecraft 10,000 km apart! And the craziness of how the star-shade works makes me want to reconsider my physical optics!
NG also has great concepts for new missions that would be ambitious but affordable. One is a telescope that starts small and grows with robotic servicing missions. Another is a pathfinder telescope on the ISS. Another is a telescope that is highly asymmetric in mirror shape, to get good angular resolution but still fit in a launch-vehicle fairing. It was a dramatic set of presentations, in part because the hardware engineering is so impressive, but in part because they are thinking of full system engineering (including software–hardware trade-offs) to control budget and make things fundable.