I agree. I've just been learning how to use new quizzes in order to create about 30 listening quizzes for English as a second/foreign language students. Each quiz will pull from at least 3 question banks, and each bank consists of the same set of items (as few as 5 and as many as 25), but with a different voice speaking the items. So let's talk about the set of item banks consisting of 25 items each. For the Voice 1 bank, I edited each item, embedding the Voice 1 recording of the spoken phrase. Now I go to create the matching bank for Voice 2, which I had already duplicated before adding the audio clips. But the items are presented in seemingly random order (though I now know they're ordered by time of creation), which means that for each item, I have to search through the Carmen file folder with the Voice 2 audio clips, which adds (conservatively) 5 seconds per item edited. And then I'll need to do the same for the Voice 3 bank, and hopefully eventually a Voice 4 and a Voice 5 for a diverse set of voices. And then I'll need to do all this again for the other 20-some quizzes.
Up to now, I'd been asking myself, "Wow! Why didn't I switch to new quizzes sooner? I can finally duplicate quizzes!" But now that I find that item bank creation has lost this one piece of functionality that the legacy quizzes had, it's very disappointing.