My biggest and most salient point was about:config - which directly concerns the topic being discussed. Extensions make up for some of the deficiencies, true. That's part of what makes firefox more flexible, the ability to choose, download and configure features placed within easy reach of the user, not just your power-user. That's part of being flexible, running and (easily) configuring just the pieces you want to.
On top of that, about:config made fine-tuned configuring more available, while firefox got a simpler base UI at the same time. Meanwhile, firefox lost none of it's popularity. Gnome has made fine-tuning LESS available; time will tell if that makes it more popular, but I think not.
As I have said, repeatedly, I have no problems with 'sane defaults' or simplicity as a base. It's the fact that Gnome is harder to configure than it has to be, harder than it used to be. You think that's a good feature, I think that's a problem. I can't see people beating down the doors for more difficulty in configuration, you do. You think that there is a solid wall between power users and regular users, I see a painted line. I have no problem with locking down a desktop when necessary; that is NOT the same thing as making it a PITA to configure.
And - insist I'm complaining all you like; I'm not. I simply won't use it until it's done. If I think it's done 'wrong', if it's a pain to use, I won't use it at all. I haven't badmouthed Gnome, the developers, or anything else but expressed concern that the direction Gnome is headed will marginalize it. My ONLY complaint about Gnome is that it seems slower to me than KDE; and that's something that I would expect to be remedied over time anyway. IOW, it's not a big concern.
And - BTW, the old saw of 'write it yourself'? I might, if it mattered to me at all. It doesn't, though.