Nice reminder.
Before GNOME 3 was released, problems were known that developers
would not try to combine different flavours.
Mark Shuttleworth/Canonical got problems, developed Unity (as
they were told to after some citations) and were locked out.
It doesn't matter whose fault that was - the result is talking:
Ubuntu lost popularity - which was harmful for GNOME and other
distros. Mint gained popularity (with GNOME 2 / MATE).
If this would be a war, generals should talk and end it.
There is no need for a special DE in a fixed and sealed design.
We need choices. Not (only) in being able to use another DE,
but changing the appearance (should be up to the distro and user)
and functionality (default being on the distro side, real settings
should be easily done by users - and important and common ones like
"focus follow mouse" should be present from day 1 after released the
first time as a stable release).
GNOME3 and Unity are quite buggy - till that very date
(my impression was Unity is better - but this may change),
options important for many users are lacking - on purpose or due
to lack of manpower ...
The user base gets smaller.
All have lost till now.
Developers should open their mind for interoperability - and put
the branding and `quality' smalltalk aside.
And start to listen what options their users need to efficiently
work under their DE - both have lessons to learn.
The time is running - not in favour of them as shown by the discussion
here.