WaW dogs are atrocious, and you can hide from heli's. I found out that in black ops, dogs will not attack you if you don't shoot. Idk if this works if your gun is silenced, but that made me more relieved rep if I made you feel better lol
I'd say helicopters are more balanced because you can hide from them just by running into a building and when a helicopter's in the air you cana still get kills. When dog's are out on WaW i have to camp in a corner focusing on killing them and not killing enimies which usually results in me dieing 2/3 times....
I dunno, the dogs in WaW were pretty effective... but then it depends which heli youre talking about, I mean if youre talking 7 killstreak the heli in mw2 is awful (harriers ftw )