It looks almost like it's from many years back, or some kind of Alpha version. The UI simply doesn't match up to the rest.
Bridge is just a file browser, nothing more and nothing less.
In its first iterations, Bridge was just Photoshop's image browser.
Unlike the other applications in the artificial "suites", it doesn't edit anything. It simply hands the files to the appropriate application, whether that be Adobe Camera Raw, Adobe Photoshop, Adobe Illustrator, or even MS Word.
Inconsistency between or among applications in the artificial "suites" should come as no surprise.
The "suite" concept is a fabrication of Adobe marketing and bean-counting types. The engineering teams are totally independent of each other, they are not only in different buildings but in different cities and states of the American Union, even in different countries.
The fact that they have little if any communication among them is highlighted by requests occasionally made in these forums by top Adobe engineers to let the other teams know when there are problems in one application that impact our workflow in another one.
Still, I can't help but be annoyed by the lack of consistency.
I can imagine that, but sadly enough Adobe is a very large company with many locations and different teams. The moment they started Creative Suite many parts where already more or less matured and others had to be build from Scratch.
Ps in CS6 is version 13 while Bridge first appeared in CS2 and is yet on version 5 in CS6
But like you I'm very frustrated about the lack of development and progress Bridge has shown in the past cycles. Consistency is needed, not only in UI, but also in menu's tools and shortcuts. Again sadly enough there is still a long road to travel, many users are used to the workflows from the past so it is not easy to match everybody's wishes I'm afraid.
On the other hand, You can use preferences to change UI colors to personal taste as you can drag and resize the panels in max 3 columns but many rows and tab to match your personal needs and save it as a custom workspace