User blog comment:AdvancedRookie/Some random Killstreaks/@comment-1079585-20100208204240

Overpowered unless it was at least an 8 death streak, and it wouldn't really fit in with the current death streak theme. So far, all of the death streaks are temporary perks. Juggernaut on roids, Last Stand on roids, Martyrdom, and Copycat are all very perk-like, which is why they can be switched from class to class. An anti-air missile is more in line with killstreak rewards, but I just wouldn't see the point of such a thing. Sure, from a utility standpoint it would be very helpful against enemy AC-130s, but for each thing that is implemented into a game the designers can't just think "Would this be useful?" If they did that then everything would make it into the game. What they have to do is ask themselves, "Would this be useful, fun, balanced, fair, and will it fit into whatever role we are assigning to it (death streak, perk, killstreak, attachment, equipment, whatever)?"