Biometrics are a non-starter. Part of the appeal of reddit is anonymity. You can post in your city's sub while getting your rocks off in some 18+ sub, from porn

Biometrics are a non-starter. Part of the appeal of reddit is anonymity. You can post in your city's sub while getting your rocks off in some 18+ sub, from pornography to watching Russian dismemberment. Removing gamification would be a big one. Karma farming is a big part of the bot network.