As they say, "Never is a long time."
As of right now, Animate is out of beta, so it is a released product. Currently, we do not have the functionality to paste editable vector art from Illustrator into Animate or be able to support shape tweens, but this does not preclude us from adding the functionality in the future. I can tell you for sure, our engineers on Animate are constantly at work on the next releases of Animate, each with different new features. As it's a young product, it might not be as feature-rich as Illustrator or Flash, but please remember that both of these products have been in development for over 10 years each. We're working on integrating more closely with other Adobe products, as you can see from our recent addition of Edge Web Fonts to our panel, and our support of Digital Publishing in Illustrator.
Hope that helps a little bit - while I can't tell you precisely when a feature may or may not be included (or whether we'll do it at all), I can at least assure you that we as an engineering team do listen to the requests made in the forums. (Not punting you out of the symbol editing stage when you preview in browser? Done!)
Thanks for the reply Elaine
Have been looking around but struggling to find any evidence on any progress on this, specifically the shape tweens question.
Could you please update if this has moved on?
Vectors are not available in Edge except through SVG. You can use GreenSock for that.