I find the searching to be vastly useful, and if you need to see the download location, just right click any file.
Sure, great, they put info in another spot. That's cool. But zero points for removing functionality in favor of a harder-to-find implementation. I think it's great they put a search tool in there. But guess what? Files are downloaded to my machine which *gasp* has a search utility. I think they were trying to be too much like Apple and MS (xerox machine) by placing the damn search in every.effing.place.they.could.
Firefox 3 was an attempt to make a 'native' feel for each browser inside of each OS. My theory is that they made this window uniform for all versions so users could easily switch between the browsers on different OS's and know where things were.
Yeah, it sure looks like your typical linux dev UI mess, I'll give you that. Massive font sizes (comparitively) and UI elements that are both out of place and don't make sense. Regardless of the reason, it's an ungodly mess of a UI design choice. I would have more faith in you to put together a better looking UI than I would the mozdev team at this point.
If this is really bothering you, perhaps bring it up to the Mozilla developers themselves on their mailing list or irc.mozilla.org. This is what open source software is all about, feedback and getting users' opinions heard.
This is not in my job description. And you fail for using a fruity nick still, DoctorNick.