(adsbygoogle = window.adsbygoogle || []).push({}); If Treyarch implamented pro killstreaks. Each killstreak would have there own set of challenges. For example: SPY PLANE Pro's challenges would be, achieve 5 spy planes(not at once) within the first 30 seconds of a match. The Pro spy plane would be active for 60sec instead of 30 and it would refresh anemy positions quicker. Care Package Pro would give the user a higher chance of receiving a higher killstreak and the care package would drop quicker. Challenge Ideas: obtain 10 care packages within a single game, kill 5 enemies with the care package. And so on, I'll add more when I have more time later.

might be quite cool, but attack dogs, gunship and chopper gunner are already really powerful

I know, but each pro k/s would require you to get 2 more kills, 12 k/s would be 14 kills. For attack dogs, they'd be faster and you'd have more in the battlefield at a time. Chopper Gunner would have 3 flares and the turret would be easier to manuver and things like that. With the Gunship, you'd be able to leave the battlefield longer and have controllable flares, and the rockets would have bigger splash damage.