My dream FROST-like setup is 1 of n signature scheme where:
1 - each device/app creates its own private key that simply cannot leave the device (like a security chip)
2 - new keys can be added/rotated to the scheme without changing the main pubkey.
3 - encryptions to the main key can be decrypted by any other key from the n set.

This is probably impossible right now, but who knows what the future holds.