I agree with your analysis Ben. This is mainly symbolic but also practical given that some indeed want to fly into one and out the other. But it won't go further not least because Dubai and Abu Dhabi are deeply competitive and the latter - which is by far the richer emirate (remember they bailed out Burj Dubai which became Burg Khalifa for that very reason) would never agree to see the Etihad name disappear.
But it's a step in the right direction and possibly a reason why the new Etihad CEO was bullish about network re-expansion recently, given that Etihad may want to ensure their network reach isn't significantly less than Emirates down the track. This way, they can do t in a mutually beneficial way rather than compete with Emirates, as James Hogan tried to do (and failed) when he ran Etihad.