Why couldn't this have instead been fixed by having Firefox listen on both, and then having remote control check X11 first and then if it didn't find it there, then fall back to D-Bus? Wouldn't that have fixed the problem that motivated the change, but without breaking the use case with X11 forwarding?
It seems for me that this remote control using the X based protocol was never meant to be a feature. Probably the mechanism was created before D-bus existed, was meant to be dropped once a better solution was created, but never was done until now.
If anything else, D-bus seems to be the proper protocol for something like this, since as the author itself said, it is simpler and more reliable.
