I think there may be some confusion here. Reading the original tweets from @featherless, I don't see any intent to actually change the end-user design. For example:
> This evolution of how we approach design for Apple platforms has enabled us to marry the best of UIKit with the highlights of Google's design language.
I'm reading this to say that custom UI components will be replaced with UIKit components that will be customized to have Google's design language. But at a high level, the apps will continue to look the same as they currently do.
> This evolution of how we approach design for Apple platforms has enabled us to marry the best of UIKit with the highlights of Google's design language.
I'm reading this to say that custom UI components will be replaced with UIKit components that will be customized to have Google's design language. But at a high level, the apps will continue to look the same as they currently do.