The things I hate about the announcer is when he notifies you about your equipment, it's your equipment you should be aware of it yourself. The announcer gives away your position if you go in a building taking out enemy equipment. That is just stupid, because equipment should be the players problem. So there should be no notifications to equipments.
The announcer announcing kill/scorestreaks or objectives is alright, considering it's a game, these are the only things he should announce. Maybe even the time remaining, etc.
In regards to BO2, the worst announcement is when an enemy lightning strike is called. It's too delayed, you hear it after you've been hit. So there is no need for an announcement for that scorestreak. I get it that it's a "lightning" strike, meaning fast, but if you're going to mention it too late don't bother mentioning it. I'd rather hear the announcer say, "Enemy Lightning Strike inbound, oh shit sorry, guess I was too late".