IYO do/did these provisions in the license really have teeth? The idea of steemit inc actually litigating a claim of copyright infringement against a witness running an unauthorized version seems pretty far fetched to me. Was it ever discussed what would happen if someone just said "fork your license im running what i want"?

At best, it would be very expensive, very drawn out, and terrible PR. At worst it would be an asian land war like RIAA is fighting with filesharing.... constantly scanning the network for new witnesses running unauthorized versions and pursuing them.