Yes, it will submitted soon™.
Other than that, it seems you are well aware of the trade-offs involved, which was the goal of my original reply. I would only add that you can also provide default implementations for protocols, if you would like to, exactly as you do for behaviours (but they are also discouraged for exactly the same reasons).
I always find porting such systems fun, exactly because of the challenges in converting from OO to FP. 
