"I thought FF29 was supposed to be the most customizable Firefox yet?"
Whoever told you that was incorrect, as far as I am concerned. Firefox still is more customizable that the "competition", but not as much as previous versions were.

The Home button can be moved, but the Back / Forward combo button is attached to the Address Bar - they can't be separated.

The combo Stop / Reload button is locked in the Address Bar.
The old "Activity Indicator" is gone. Deemed unnecessary with the loading animation on the left corner of each tab, where the Favicon appears once the page is fully loaded.

https://support.mozilla.org/en-US/kb/how-to-make-new-firefox-look-like-old-firefox

Many users are installing the Classic Theme Restorer extension.
https://addons.mozilla.org/en-US/firefox/addon/classicthemerestorer/
But I don't think that is going to turn out to be along term solution. As users start installing other extensions I think they are going to run into compatibility issues where the new extension "expects" the user to be using what Firefox came with - not the "retro" features.

Yeah, hopefully Firefox fixes this and unlocks those elements to be individual elements again.

The old "Activity Indicator" should not have been deemed unnecessary imo. In terms of best UI, having an element always in the same XY location is best. The activity indicators on the tabs can be in many different places all along the top of the screen, so the user's eyes have to dart around trying to find it.

Thanks for the links.

Classic Theme Restorer does the job