I'm starting to get really excited for this game. They've made so many good changes from previous CoD games.
Some great things they're doing IMO:
Better perks: No commando, no stopping power, no juggernaut, no sonic boom/danger close. No stopping power is a huge change for the series since like 99% of people rely always on stopping power, its like being freed from a drug and we're finally able to try out other perks they have to offer! Commando was the worst idea ever, I think everyone's glad its gone. And no perk that increases explosive damage is a major plus, I'm sure there will still be noob tubes but without the 40% damage increase of danger close they won't be so unbearable.
Better killstreaks: No nuke/emp and making the highest streak 11. Also they're making only weapon kills count towards your streak which is awesome (unless it promotes more camping)
New Modes: Wager modes seem great, and combat training is cool. Zombies is a given even though it hasn't been confirmed yet. No way they disappoint millions of people by not including it (unless they're gonna make it a $15 add on or something)
CoD points: Seems like a very interesting idea as opposed to unlocking things just by ranking up
Fixing annoyances: They're putting the shotguns back in as primaries instead of secondaries which is great. It was stupid in MW2 how you could have an assault rife/SMG and an overpowered shotgun without something like the overkill perk from COD4.
Edit: I hope they fix the knifing too, its way overpowered in MW2 even w/o commando. I'd rather see them make the knifes too weak than too strong.