Maybe renaming the instance variables to reflect their UTC nature would help, but there is a difference between internal representation and external behaviour - if it is documented that seems OK to me.
The #midnight example probably needs an extra normalisation of the internal representation, which would indeed shift it to what you would expect.
Constructive criticism is always welcome, but these changes to DateAndTime were made many months ago - with great effort. Yes, there is still work to be done, and although it is maybe logical, it is a bit dissappointing to hear it right after a release.
We were expecting that :) and this is why we drop the idea of a release candidate :). We will produce a summer edition and probably a batch of fixes for 2.0. once they accumulate :). Stef