I think it is really important that we do not let our uniqueness be diluted but am I wrong?
But, like, how?
So you’re Meta, and you want to Embrace, Extend, and Extinguish ActivityPub. Maybe you add some new nonstandard feature that’s not compatible with existing Mastodon clients. Annoying, but are people really going to sacrifice everything they like about their favorite client so they can take advantage of some random proprietary feature?
So if they become so incompatible that they completely separate, doesn’t that basically result in the same thing as OP’s goal of total defederation?