It's bad enough that Discord seems to be vulnerable to attack. But now they want to hold on face scans and ID's that directly tie to their accounts? It's already not smart, but especially dangerous for public figures like streamers and vtubers. Not only can it dox their appearance (if they are hiding it) but also give the insane stalkers direct ways to harass them or assault them at home.

However I think Discord is far too embedded for communities. Whether that be social or development. So I don't think we'll see a big exodus. Having teen mode be the default will just mean that NSFW flags on channels or content will be a death sentence for that board or community. Similar to how Reddits big push to shove NSFW into a corner has gone. There are obvious examples like adult content that are NSFW intentionally. But things like art or cosplay can easily be twisted as NSFW and it just shuts down the reach of these kinds of artists.

Unfortunately most people are dug in now and it takes absolute extreme actions to get people to move. The fact that X is still around should be clear evidence of that. It's draining over time but that kind of universal community has not be replicated. Just a couple different echo chambers.