You've mentioned Vanguard using Descent of Angels before, and either you are sadly mistaken or my codex is misprinted. According to the codex I have, Vanguard Veterans get ATSKNF, Combat Squads, The Red Thirst, and Heroic Intervention, but NOT DoA. I've also checked the FAQ for Blood Angels, and did not find anything about it mentioned (though I could have missed it).
That being said, I'm well aware Vanguard can be devastating with lucky rolls and what-not. It's just, without DoA, you're relying on luck a little more than some people are comfortable with.