With regards to the addition of the Trix editor, there were some people claiming that it should not be included in the core framework (like a few comments in the video introducing it:
https://www.youtube.com/watch?v=HJZ9TnKrt7Q). Personally, I think it is a great addition as it offers just the right amount of features, with a simple design. Also, the fact that it was created by developers at Basecamp makes it more comforting knowing that it will be maintained well.
As always, great work from the team. Thank you for all your hard work. Can't wait for the full release :)