Like it or not, CoD multiplayer games have been focused since the beginning in giving power to individuals. That is, it's easy to be killed by someone alone, preferably while being tucked away somewhere throwing grenades at you. Games that don't focus on this are more teamplay-oriented, in which other classes support the troops approach. It's sad to say it, but if you want players to be autonomous, you need to give them a chance to break all ingame balance, and that's where grenade spamming comes in. There is still people in Bad Company 2 that just sit on top of an ammunition box and keep shooting tube grenades until the end of times but it is not, by any means, as severe as the CoD spamming because said person tends to be dead once two or three people decide to blast his position sky high. I'm not saying it's the way to go, or that those games do not suffer from balance issues -I've read terrible, terrible things about the Blackhawk on BC2-, but I can foresee many years of complaining about grenades in the CoD series. In fact, I'd bet a lot of people expect to be able to grenade-spam when they buy a Call of Duty title.