I feel that this decision is wrong in many ways.

* Angular and RxJS go hand in hand from the beginning. In fact I came to know RxJS thanks to Angular. I don't think this was a bad decision. It was a nice standard way for Angular to be reactive. For me the places where it was not used, like `@Input` or lifecycle hooks, feel out of tone from the rest of Angular.
* How do you plan to remove or replace Angular's dependency on RxJS without introducing a massive backward incompatibility breakup like in the AngularJS -> Angular 2+ era? Don't repeat history but learn from it!
* If you manage to not create backward incompatibility issues, then why do you think that introducing input as observable will?
* It _already_ is possible to merely see the usage of observable/observer as a Subscribable pattern. RxJS was meant to be functionality around this pattern. But because Observable was not an ECMA standard like Promise, Observable was included in RxJS. If I remember correctly, Ben Lesh regrets his decision not to make Observable a separate lib apart from RxJS, because now the two are seen as one while in fact they are not.

I hope this decision is reverted soon and Angular will return to it's declarative reactive path instead of holding on to partly forcing users to use error prone imperative reactiveness.