User blog comment:Bovell/Color blind assist option for Modern Warfare 3. Killstreak system reworked./@comment-99.41.18.28-20110708174008/@comment-4081799-20110708201209

Black Ops' changes may not have been entirely beneficial, but I would contend that removing 'stacking' from killstreaks is one of the best ideas they implemented.

Having your last killstreak count towards your next is a relic of the days when the highest reward you could get was for seven. In MW2, on the other hand, higher killstreaks are game-changers, and you can get them without having actually earned even half of the requisite kills.