Simplifying the interface of the terminal would not be accepted by most users because, as ethnographic studies show, they take pride on manipulating Bloomberg's current "complex" interface. The pain inflicted by blatant UI flaws such as black background color and yellow and orange text is strangely transformed into the rewarding experience of feeling and looking like a hard-core professional.In other words, the Bloomberg Terminal is one of a class of items whose bad design is a feature serving a higher-level social function; in this case, the function is that of being a badge of proficiency or status, and an artificial handicap to keep usurpers out. In this way, it functions somewhere between the tail of a peacock (which is expensive to grow and makes one more visible to predators, but having one (and being alive) also acts as proof of fitness) and the regalia and rituals of Freemasonry back when it was a force to be reckoned with. Of course, secrets are inherently leaky and can hold power only for so long, so sooner or later, perhaps someone (possibly Apple or Google?) will come along with a more elegantly-designed system that will demystify what it does and, in doing so, hole Bloomberg's boat below the waterline (unless they do so first).
One thread in the "command-line vs graphical-user-interface" debate (which has run continuously since the 80s) is a lot like this.
(Ah great, here comes the text-editor flamewar. :-) )
I use vi, and not out of machismo. I use it because (a) once you've mastered the learning curve, it is easy to do things quickly (precisely, to go from doing things yourself to commanding the text editor to do relatively complex repetitive tasks automatically, without the delay of navigating dialog boxes to do so), and (b) because it's not as top-heavy as, say, Emacs (which takes too long to start up for casual editing sessions and is too big to be a simple text editor and yet, being single-threaded, is inadequate as the operating environment its advocates hail it to be; having your editing sessions freeze while it fetches your mail is not good enough).
Having said that, when I code anything larger than a throwaway script on my MacBook these days, I use TextMate.
IMHO, CLIs and GUIs are tools for different functions. If the task involves the user picking elements and doing simple operations on them, a GUI is superior. If, however, it involves instructing the computer to do more processing (i.e., "delete all *.o files older than seven days"), a CLI is superior.
<i>The pain inflicted by blatant UI flaws such as black background color and yellow and orange text</i>
Amber or green text on a black background may not look "modern", but it's certainly easier on the eyes than most popular colour schemes. And if that's his biggest gripe, he's just confusing UI design with design.
<i>Having been a user of the Bloomberg Terminal for five months, it took me a week and a few painful hours to handle it, and I am no genius.</i>
"A week and a few painful hours", whatever it means, doesn't sound like too much time to master a professional tool. It's not a casual game, it has to be efficient, but not necessarily intuitive. And efficiency is a subject that the author, strangely, doesn't address.
But then, I use evilwm managing mostly xterms running a shell or vi, so I can't be trusted.
<i>The only real impediments were the unbearable UI, remembering which key to push to make the "magic" work, and having to go through the 86-page manual.</i>
So, it has an 86 page
... So, it has an 86 page printed manual but no online help? I've seen worse.
Arguments about text editors aside, I really like the bad-UI-as-peacock's-tail analogy as presented in the last paragraph of your post. I think when this analogy is made clear we are likely to see it all over the place: fixies and manual cars spring to mind. ... Re the GUI example, I recall hearing this argument a lot in the 80s, when the Mac was new and MS- and X-Windows were struggling to find acceptance, (paraphrasing) "This GUI is for noobs and I don't need it". The acronym "WIMP" didn't help. In the IT community it took a long time for user-friendliness to be accepted as a desirable goal in itself, independent of the debate about which UI was more user-friendly. This was tied in with the computing's shift from mainframe to PC, which many in IT were not in favour of.
Not being a financial trader, I've never used a Bloomberg Terminal, and thus have no idea whether its "bad UI design" means just that the UI is out of step with common practices and has a steep learning curve, but has advantages which make it worthwhile (as is the case with vi), or whether there is indeed some degree of masochism involved in using it.
That's the same reason people use the vi editor. It's a macho thing! :)