I think the AoE nature of Howling Blast is huge.
This is the one thing, that (in my mind; I might be unfairly biased however) puts the composition ahead of what I can do with a set of Ferals; the healer is moot, since either comp could run 4x/5x DPS and 0x/1x Healer.

Howling Blast applies damage to a lot of characters at once.
We will have HB glyphed, so this means Frost Fever on several targets at once.
And talented, Frost Fever is a snare.
So we a ranged AoE snare/dot, and punish those who choose to cleanse this dual effect... by re-HBing them, for damage plus the snare/dot again.

If Howling Blast was a single target... that would really suck.
Other changes wouldn't be as devastating, for example if the damage were capped or divided between the targets... we'd still be AoE snare/dotting several opponents, and they'd be unable to cleanse that.
The range is excellent, especially for the melee team.
Pretty much only need to IWT, to ensure we're facing the target.

But, not sold on this being an over the top team if HB were single target.

A lot of other compositions will also put out single target DPS faster than any Cataclysm era healer can keep up with.
The AoE nature, is what puts the team over the edge, imo... the opposition will have several targets to worry about, and if one is bubbled we can switch to another target easily enough.
If it were single target, this would still be a killer composition but not the clear winner.

As Shodokan pointed out, it's unlikely to be nerfed because of boxers, when we make up 0.08% (or whatever) of the player base.





The necrotic strike, basically ensures the main target cannot be healed.
So that is very strong pressure.
It almost guarantees a kill, in the initial attack (while we're immune to CC type effects), unless they have an immunity effect.

The only defense to this really are effects like Pain Suppression (effectively doubling the time to kill the target) or bubble (where the target cannot be killed for the duration).

If the target gets protected, our effects like Anti-Magic, Lichborne, Etc, have a relatively short duration; we'll have them for the initial engagement, but if we fail to drop someone in this time... we become rather vulnerable to knockback, fear, etc (but not vulnerable to snare/roots thanks to Death Grip).
We'd have a good chance at killing someone, during the opening because they'll likely have a few hurt toons for us to choose between, because of the AoE nature of the Howling Blast.

If we can down someone immediately, particularly if that is the key class for their composition (arena) or the most dangerous healer type around.... we get a huge edge.
If they bubble the initial target and survive the opening... the match gets a lot harder.

That reason alone, makes me very strongly consider a Disc Priest, for the Mass Dispel. Without a bubble or damage reduction effect, we basically have a guaranteed kill.
But the Disc Priest is a lot more fragile than a Pally.
So the decision is not easy.

Which is preferable:
a) Our healer is more fragile (Pain Suppression, PW: Shield, Self heals... for reduced damage but not negating damage), but virtually guarantees the initial target is dead. Fear Ward and Mass Dispel, superior AoE healing, etc.
b) Our healer has superb survival skills (bubble, plate, shield), but if their composition contains a skilled Pally (also has bubble), our initial target has very high survival probability.

I'd lean towards (A).
Because, in arena if they're down a healer in the first 5-10 seconds, they've probably lost even if we lose our healer right after.
In battlegrounds, if the healer/fear/knockback threat is gone fast, the mass of enemies probably don't have a chance.
Conversely, if our healer (B) survives the initial burst (assume Bubble is not dispelled), but occasionally we don't down a target in that initial opening period, how does the team fare without the defensive cooldowns aside from the trinket?