I just think it's an awkward design - there's no tell, as you said, and the next targetable object takes a long time to come up. You get something similar with Imdugud's add phase, but it's much cleaner because you get a massive telegraph and the adds are quickly targetable, so the impact on your flow isn't so bad. In this case, the impact is pretty bad, because the best way to deal with it that I can think of is to Blizzard 3 early and wait (maybe throw out a Scathe if you're feeling frisky, but you're still gonna be waiting on that next target). And because you'll likely be doing it with DF parties that DPS at different speeds, you'll have to feel it out pretty much every time.