https://discord.com/blog/usernames

1. It's going to be a race to pick our preferred usernames. People are going to be hacked because others will want their usernames; This will lead to an entirely new wave of new scams

2. A very big chunk of people buy nitro specifically so they can have their custom discriminators. This removes their reason to still support Discord

3. A lot of handles will consist of random underscores and numbers, which makes them even harder to memorize than the discriminators and therefore negate the positives

4. Discord is not Instagram/Twitter/Youtube. Discord is a platform to hold conversations. More accounts want the same name, so discriminators are a good way to distinguish between them while satisfying everyone with the name they want

5. The update breaks a lot of community-made bots that are an essential part of Discord nowadays and encourages users to use bots like Mee6 now which cost a fortune

6. Handles will make stalking easier, since they are reused on a lot of social media sites and provide a real danger to people

The update is ugly, inconvenient, and will make things a lot more difficult than they need to be for the actual users.

Change is NOT always better. Don't fix what isn't broken.

https://support.discord.com/hc/en-us/community/posts/14337329256983--Do-NOT-add-The-new-discord-usernames-system
https://twitter.com/TCOOfficiall/status/1653834211172687874