@jcast @9x0rg we have a good discovery mechanism, implementing OMEMO:2 doesn't break compatibility with other clients at all (Libervia that I maintain do implements both, as well as OX, and stays compatible with other clients).
The only thing that would make it incompatible is encryption by default to OMEMO:2, but nothing prevents to stay on OLDMEMO by default during transition.
But it is works to do the implementation, and client developers are all overwhelmed, that's the main issue.