As it was already mentioned, this is not exactly a proposal for a redesign and even less for a rebranding of Notion. It is a re-imagination of Notion as it is now, with the addition of new elements - and for this reason I tried to be as faithful to the current design as possible while addressing some personal changes that I would like to see in order to improve the interaction with the platform.
Still, most - if not all - of the new functions could be easily implemented with the exact same base design that Notion currently uses.
The biggest change with Notion's base interface is in the top bar, which I have always thought could use a bit more distinction from the actual content, so I gave it the same background as the sidebar; the breadcrumbs also now have a more polished look so it can be more easily recognized while still not interfering with the content. I then decided to put the current text options ("Share", "Updates", "Favorite", and "...") under the "Options" button on the right in order to fit two new options: "Notes" and an edit button, which I describe in this section: 3. Notes everywhere & formatting bar. Finally, I still wonder if this top bar has the option to be hidden as the sidebar does.
For the sidebar, I only included a change in how a profile or member of a team is presented, a more prominent "Search" option, and the option to set custom icons built into Notion for our favorite pages to have more visual distinction. Emojis are still possible, of course 😅 - but having this new brown color option is great for filmmakers, who tend to be very visual.
Overall, colors are basically the same, and at a glance they are very recognizable with the actual Notion options and design.