Even more so.
MW3 uses the Strike Package system, which splits up killstreak/scorestreak progression into three different categories: Assault, Support, and Specialist.
The Assault Package contains many useful killstreaks aimed towards getting you more kills and executing huge game-shifting plays (sometimes), and functions exactly like killstreaks in MW2 did, i.e. the streak resets upon death. You have to stay alive and build your streak to get more rewards, and both kills and objective captures/defenses build your streak.
The Support Package works a bit differently. Most of its rewards focus more on supporting the team--better UAVs than the Assault Package, stationary area denial (remote controlled sentry turret), high-health defensive unit (Support juggernaught with riot shield and pistol), etc. The streak, however, does NOT reset upon death. It continuously builds up and up, requiring people to continuously try and get to objectives, to get into the fray, in order to get up to the higher-tiered streak rewards. This is the package that allows people who aren't as good at the game still contribute to the team in a meaningful way, and the package that divided a lot of people on the game.
The Specialist Package works more like the Assault Package, resetting upon death and focused more towards confident players. However, where it differs is the rewards: instead of gunships, care packages, etc., each reward tier gives you another perk of your choice on top of the three you get to slot in per class. 2 kills gets you your first additional perk choice, 4 kills gets you your second, 6 kills gets you your third, and 8 kills activates ALL perks in the game simultaneously. The difficulty with this package, however, is the double-edged sword that it inherently is. You obviously become extremely potent, but often power goes to the head, and you die a lot quicker if you aren't careful. Maintaining the streak takes a lot of restraint and patience.
Finally, all Packages come with the MOAB as the ultimate reward at 25 kills/points. However, unlike the Tactical Nuke from MW2, the MOAB does /not/ immediately end the game. Rather, it kills all members of the enemy team at once, activates an EMP for 1 minute, rather than the normal 30 seconds, and the team who got the MOAB gets double XP for the rest of the game.
Oh, and the best part is, the Strike Packages are dependent on the Custom Class. Unlike MW2, where killstreaks were independent of the class, Strike Packages are an additional category to choose from in your classes. You can have an Assault Class with the Assault Package, and also have a Support class with the Support Package, etc. Frees up classes for a lot more experimentation.