I have been biting my tongue watching all the changes that add-on developers are being required to make for Firefox 4, but the various theme changes that are going in which are going to cause toolbar icons to be scaled up and/or down has put me over the edge. (See bug 583231). A lot of work is going to be required by add-on developers (and artists and others) to work around these and other issues. It doesn't help that these Firefox "betas" are no where near beta quality, and involve major changes with each beta update, which means add-on developers are having to do rework with every "beta."
I emailed folks from the AMO team about this and they indicated that their role is only to communicate what add-on developers need to fix, not to work with the Firefox team in any way to represent add-on developers.
Update:That sentence above did not properly represent the email conversation. I stand by my assertion though - the AMO team does not proactively work with the Firefox team to look out for the needs of addon-developers - they communicate information after the fact. They are not on the front line saying "How will this affect add-on developers?"
So there is no one involved in the Firefox 4 process that is advocating for Firefox add-on developers. We're just expected to "roll with the punches." I understand that we're just consumers of the platform, but add-ons have built up a great deal of brand equity for Firefox.
I find it quite short sighted of the Firefox team as a whole to alienate add-on developers this much. I'm aware that this a major release, but there should be more and better messaging around these changes. And they could certainly be batched better instead of spreading them across every beta.
So please, think of the add-on developers...