Well, first, just because the diamond tweeter was implemented in one way and resulted in a particular result, it is hard to predict that different tweeter implemented by another design team will give the same outcome. B&W did acknowledge that there had been an earlier diamond tweeter design. Frankly, I see no reason to make presumptions in advance of an audition.
Second, I do not necessarily equate detail with brightness although excessive brightness can unnaturally emphasize details. Personally, I want all the details but 'au natural' and not at the expense of accurate tonal balance.
Kal