Nope. In fact, in 3.2 I dual spec tanked for those reasons. My Frost Spec was strictly for AoE, it had Chillblains, Hungering Cold, and DnD talented. It was an AoE machine, but fairly awful at single target.
In 3.3, my Frost Spec consistently pulls better single-target threat than Blood. It also does better at AoE, but not being able to toss down a DnD as often scares me.
The main issue right now is survivability, and my ability to manage cooldowns to keep myself alive.