I think what would be most welcome would be to organize the content in more digestible separate "modules". I have both the Lr3 tut and C2P2S and frankly, I can't find the time to work through it all (not a bad thing to complain about, really!).
For example, off the top of my head:
- Intro/Overview - what's new - demo sample wf's for different output destinations (print, web, book etc.)
- Library & Develop
- Soft Proof & Print
- Slide show & Web
Offer each module individually for purchase, so, for example I may start with Library/Develop and purchase Books or Video at a later date. Offer a bundle discounted price for the entire set.
Ok, that wasn't so much new features (well, not at all!) but my 2 cents on improving the product.
What I'd be most interested in seeing are the perspectives and techniques you mentioned in your last post - putting things together that I may not be otherwise aware that lead to those "aha!" moments. For example (and I have no idea just now if this is possible), can you use geo-tags (location data) in watermarks? Is this data available in Books?. I've just started working with Lr4 beta so I don't have specific areas yet that aren't likely obvious (such as PV2012, soft proof, etc.).