Finally found some time to write a draft for news post on i686. Here it is:
Title: i686 is dead, long live i686
Due to the decreasing popularity of i686 among the developers and the
community, we have decided to phase out the support of this architecture.
The decision means that February ISO will be the last that allows to
install 32 bit Arch Linux. The next 9 months are deprecation period,
during which i686 will be still receiving upgraded packages. Starting
from November 2017, packaging and repository tools will no longer
require that from maintainers, effectively making i686 unsupported.
However, as there is still some interest in keeping i686 alive, we would
like to encourage the community to make it happen with our guidance.
Depending on the demand, an official channel and mailing list will be
created for second tier architectures.