Not so much for arena's. But a boomkin can blow up anyone at the moment in a bg when given the time to cast. In rated bg's they rock. Giving them 2x 23% extra damage is pretty insane there.
And unholy dk's and 20% strength is nuts as well. Necrotic strike scales with attack power (and 2 AP = 1 STR). Not to mention the physical abilities that will rock. Both in pve and pvp. They nerf the fuck out of frost and now boost unholy like mad. Either way 4x necrotic strike is going to be fun for boxers, but i rather see balance in the game than that we can run OP comps.