Some anti-features that come to my attention off the top of my head:
* Biometric login (as of FF60)
* Dumb PR Stunts like Mr. Robot
* Telemetry
* Balrog (Analytics and browser fingerprinting on AmazonS3)
* Social API
* VR sensors
* DRM
* Google Chrome (large contract Mozilla has with them as they backport this into IPC)
* CloudFlare DNS (Department of Homeland Security partner and Tor arch-enemy)
etc...
What issues exactly? Tor Browser = Firefox ESR + some patches + some other stuff and tweaks. Before the release of the next ESR TB devs rebase and submit these patches to mainline Firefox, that's why you have prefs like privacy.resistFingerprinting and privacy.firstparty.isolate in mainline Firefox, see: https://wiki.mozilla.org/Security/Tor_Uplift
Are you talking about Web Authentication? What is wrong with it?
What's this?