I generally agree with the choice of killing off XUL, since WebExtensions has clearly won and they needed to move to it, and help participate in its development so they can steer it towards user freedom.
I think the Multi-Account Containers idea is fantastic, and the Facebook Container in particular was nice. That is a recent development, but I feel like it is an essential privacy feature now.
But Mozilla is failing, that much is true. And they just killed off their most promising blue sky initiatives like Servo, so I no longer see a future for them at the moment. If they moved to foster a type of open cloud ecosystem, along the lines of OwnCloud, that would be an interesting direction, but I don't see that happening either since I don't see much vision at the top... even though it would dovetail with Firefox Sync, Lockwise, VPN, and other Mozilla initiatives.
I am passively looking for other browsers now, however, since I have lost faith in Mozilla.