Yeah, my only response to it really was surprise, since I thought blobbing was going to be the result of giving up control to the AI, not total and instantaneous self-destruction.
It is funny you have to edit the decision files to let a Hellenic Roman Empire have its imperial reconquest casus belli. Because only Christians could possibly revive the legacy of Rome. I guess it's the Holy part of Holy Roman Empire that matters. (Actually, AFAIR, you can't even reform the Empire in the first place without being Christian.)
Will be interesting to see if the converter gives it the same treatment, sounds like it will from what Johan was saying (unreformed pagan -> generic Shamanist/Animist). What I don't get is why they didn't just make Hellenic behave as a reformed pagan religion from the beginning, it would be zero extra work and the tooltip says it IS reformed, even though the game engine says it isn't.