Summary of all changes in BO2

First and foremost: new pick 10 create a class system.
Instead of just picking your primary weapon, secondary, grenades, perks, etc. You can pick any 10 items to have in your class. For balancing reasons, extra perks and attachments and the like cost an extra point (called wildcards. basically, if you want 2 perks in the perk 1 category, you equip the first one and then equip the wildcard called perk 1 greed. and then you can equip another perk in the first perk selection. 3 points in total. so you could have your primary (1) 2 attachments (3) two perks in perk 1 category (perk, greedwildcard, another perk) (6) 2 more perks in the next 2 perk categories (. secondary (9) and lethal grenade (10) and that's your class. really cool. other wildcards besides the one that allows you to have more than 1 perk in each category includes a wildcard that lets you have 3 attachments on your gun, one that lets you have 2 lethal grenades etc.

Zombie upgrades:
instead of just classic nazi zombie survival, there's a left 4 dead kind of mode where you move from place to place killing zombies as you go. There's also a competitive mode called grief mode where 2 teams of 4 are playing at the same time and you try to outlive the other. You can do things like modify the environment (blocking passages, etc) to try and make the other team die first. There are also stat counters and leader boards with zombie mode now to tract who's better than who.

"Codcasting":
CoDCasting is something in Black Ops 2, that allows players to live stream games to the internet while commentating and jumping around the action just like a real live sporting event. While watching a LIVE ONLINE game, you can switch between each players views, view the overhead maps with everyone's icons, even listen in to what the team is saying over their microphones. Not only will this make spectating a lot more fun, it's a lot of help and VERY useful for people who like doing commentaries.

New Multiplayer features:
* You can play against bots now for your first 10 levels.
In Black Ops 2, Combat Training users can earn experience points and level their online soldier in a mode dubbed 'Boot Camp.' In this mode, players face off against a mixture of human players and bots in matches of Team Deathmatch. Players can earn full experience points and level up to a maximum level of 10, which Game Design Director David Vonderhaar refers to as "graduating." If comfort levels aren't high enough to jump into the fray online, players can stay within Combat Training and play through its 'Objective' mode, where two teams of six (3 players, 3 bots) compete in objective-based game modes. Players can rank up beyond level 10 in this mode, but are only given half of the usual XP they would earn online. 'Bot Stomp' is an experience point-free mode where teams of six players battle six bots in any gametype they choose. Playing this mode is a great way to practice skills, learn maps and modes, and is a "really good way for newer players to experience the high end game," Vonderhaar says. All modes also include public matchmaking, to make finding optimal games easier.
http://www.joystiq.com/2012/09/27/how-black-ops-2-handles-prestige-adds-levels-to-combat-traini/
* Another thing is that perks now ONLY deal with your person. stuff like making you run faster or sprint for longer, etc. There aren't any perks that makes you have better hip fire accuracy. Now anything that deals with your gun and shooting it, is changed by attachments. Attachments like laser sight helps hip fire accuracy now. Also, no more pro perks.
New game modes, some game variants of classics like headquarters and the like are now being called things like Hardpoint.
* They changed Domination so that it is a round based game. Also made a multi-team team deathmatch.
The perk that makes you invisible to UAVs is changed. Now, if you're standing still, you will show up in the enemy's UAV as if you didn't' have the UAV invisible perk on. This will hopefully destroy campers. Also, another anti-camper tool is a new red dot sight that sends out a pulse when you aim down the sights and allows you to see through walls. He later made it so that if you're staying still because you're planting or defusing a bomb or controlling a score streak, you'll still be invisible.
* There is now an attachment for your snipers that lets you use your iron sights with the sniper. I'm not sure how I feel about this one though…there might be way too many people running around with iron sighted snipers. Could get annoying. They also added a bullet trail in the air for sniper rifles, so you can see where its coming from.
* Your guns don't prestige with you. They prestige separately. So you can prestige your guy to go back through all the levels, but your guns don't de-level.
It's in the future! So all new guns and killstreaks!

Call of Duty elite is now free for all players!
Unlocking items have been changed now. Instead of just unlocking anything, or the CoD money system from Black OPs 1, it has been replaced by something completely new. Now, every time you level, you get a point. And you can spend that point on perks or guns or wildcards. There is more content than there are levels! So you'll have to choose wisely and will give players more reasons to prestige and move ahead.

Killstreaks? nope. Point streaks? nope. In this game, they're called score streaks. So instead of 3 kills and you get a UAV, or 3 kills/objective points and you get a UAV. In this game, a UAV is worth something like 325 points. So that would be like 3 kills and an assist. Or a couple objective kills (Flag defender = +150) and an assist. You get it.
One of my favorites, league play. League play is a LADDER BASED SYSTEM IN CALL OF DUTY. You are grouped with people your skill level. The first few games you are grouped with randoms and it places you in a particular skill group based on how you do. And then you move up and down the ladder (kinda like Starcraft 2). There's also no join in progress for these games!
Killstreaks can operate by themselves, or you can control them. This isn't all of them, but there are a few where you can release a drone and it goes around and kills people if you want it to, or you can control it. Or you could release it, control it for 10 seconds, realize an enemy is near you, stop controlling it, kill enemy, go back to controlling it.

[b[Singleplayer[/b] "Strike force" mode:
The single player has these awesome side mission type things called Strike force missions. You control a WHOLE squad, and you have to complete an objective however you want. Its a SANDBOX STYLE mission where you can solve it in many different ways. You can play as the squad down on the ground, you can play as a chopper and gun down enemies from the air, you can play as a UAV and direct the squad to different waypoints. It basically just takes away the complete linear feel of CoD single player campaigns.


TL;DR new killstreaks, new weapon attachments, new gamemodes, new anti-camp measures, new "perks", the pick 10 system, and gamemodes re-done.

crappy will finally get killstreaks because of objectives!

Well yea, its cool that they started to realize they need to cater to the player that plays for the team and to win, as opposed to the one that can camp best.

Yeah, I'm excited for the fact that they light fuckers in the corner up like christmas in goddamn vegas.