They should just put a toggle for it under the Customization page. I think that would be the simplest way to placate peope that dislike it. (Yes I know you can about:config to fix it, but a toggle makes more sense.)
I can handle about:config, but if they take it away, that will be very frustrating.
For me, the bigger address bar is just as bad as an advertisement: it's trying to steal my attention, except in this case no one else is benefiting from doing so.
If they remove the option, I hope someone smarter than me can come-up with an add-on to fix it.
That seems insulting to the Firefox devs. Firefox's devs are clearly better than that. The Customization page is pretty bare, they can still add it there without looking like your image.
What a time. Now every option is either a) not available b) hidden somewhere where you need the Internet to find it (chrome://flags, about:config, registry ...) and c) probably removed in the next update because "people didn't use it anyway"
The picture you posted is a positive example. An example on how to customize the software you use.