Hiding GUI elements for new users (less overwhelming)

Ah, yes, I misunderstood. So, the elements would be hidden at first per user.
There is no such feature right now. A custom theme component or plugin could probably do that, but it would need the option (per user) to reveal all the features for users who already know Discourse.

It’s only slightly related, but Discourse’s working on a new user tips feature to guide new users through the interface: