After all of the work that was done to get the DateTime into core, for various reasons, improvements to the module didn't progress at the same rate as the rest of 8.0.x. As a result, there are some very old issues in the queue (I have triaged a lot of them), and there is some work that needs to be done both on the module and on date handling in core in general. Thankfully, I don't think there is anything that can be considered a release blocker (though we do have some bugs that can be addressed outside this issue).
The purpose of this issue is to (1) discuss what needs to / should be done in 8.0.x, (2) discuss future plans that need to be deferred to 8.1.x, and (3) discuss/track this in one place as a lot of it is interrelated and we can create child issues.
Core Features
#2632040: Add ability to select a timezone for datetime field.
#2627512: Datetime Views arguments don't support timezones
#2161337: Support for end date
#2305073: D8: Date repeat feature requests
Developer Experience (DX)
#2489476: Provide Views integration for datetime fields used as base fields (probably dependent on #2337515: Allow @FieldType to customize views data)
Investigate using Symfony 2.8+ Clock Mocking in tests.
User Experience (UX)
#2567815: Add week, date, and year-month Views argument plugins
Documentation
XXX
Testing
#2498619: Unit tests should use a default timezone other that UTC
