Amazing! That will save me a lot of time. It's not very clear though that it collapses the whole page. I would have never known without you pointing that out 
Agreed, but it's tricky. Because big redesigns demand quite a lot of effort and require both programmers and designers to work together.
If I can suggest anything, I would open a sticky thread (if it doesn't already exist) where designers could post mock-up's for all web-based services. Mainly Rusdoc and Crates.io. The core team could then take their time to review the mock-ups. The community could give feedback. The designers could improve their mock-up based on the critique. And when the Core team feels like they have a strong design they could start to implement it.
This would give a centralized place for all design discussions until the big redesigns actually happen.