Zero telemetry. The recent release of the Mullvad Browser[0] is a godsend, but it's not a Chromium fork. It's based off the Tor Browser Bundle.
But if we really need a good Chromium fork, Ungoogled Chromium[1] is a good choice.
[0] https://mullvad.net/en/browser
[1] https://github.com/ungoogled-software/ungoogled-chromium
Access to all APIs including Google specific ones like Battery Status, with appropriate permissions for the sensitive ones.
Fast update cycle, security patches in Chromium need to be in the app store within days.
Bookmark sync, preferably with SyncThing friendly files and folders.
Do not do the thing where you rewrite a 100KB file every 5 seconds and cause GB per hour of drive wear. Another killer app there if you can do a kiosk friendly zero drive wear mode.
Native BitWarden integration.
Something like Mozilla's cancelled FlyWeb project, preferably with the ability to do that kind of thing over WAN, not just LAN.
All P2P features cryptocurrency-free.
Private mode should have TOR built in if you want to have a privacy focus.
And of course, cross platform support, I'd never use a browser that doesn't also work on Android.
Full setting menus like Vivaldi.
Zero animation.
Built-in domain blocker so that I can cure my Internet addition.
Stop fucking ask me to save password.
Split screen.
Gray background => #000000.