Entertaining. Very.
Now, I only play CoD4 Hardcore, as I have no interest in emptying half a magazine into somebody just to bring them down (figuratively speaking). Still, these are observations I've made from CoD and other games:
1. Complaining about Grenade Launchers, Last Stand, Martyrdom, "cheap" tactics (i.e. camping) and so on is not the mark of a skilled player. If anything, it is the mark of an unskilled player. Consider these easy solutions to each of the listed problems, respectively: shoot the bastard first; continue firing at the bastard; pay attention to the sound of grenades dropping; grenades/grenade launchers and/or flanking tactics. And for all of these problems is the one overriding solution: you are using weapons designed to be fired at distances greater than the blast radius of a grenade. Use them at that range.
Remember that a skilled sniper may be good, but he counts for little next to the unskilled camper who has racked up twice as many kills and half as many deaths.
Basic rule of thumb: if you're complaining about something solely on the basis that it makes it easier for someone to kill other people, while still acting within the confines of the game (that is, not a glitch or cheat), then you're probably just sounding like an idiot.
2. Now, of course there's an inherent problem with "shooting the bastard first:" CoD's damage system. In standard game play, it's not as viable because even an assault rifle requires several shots to bring the guy down. This, however, leads back to the question of why you aren't firing at him from a distance and behind cover, like a sane person would do.
3. I haven't played any of the games past World at War, so correct me if I'm wrong, but the map sizes often are ridiculously small for the many of the weapons used. Pretty much anything past a carbine/automatic assault rifle is often somewhat overpowered compared with the lighter stuff.
4. In the interest of fairness, there are two things inherently bad about Last Stand and Martyrdom that might necessitate removal, or at least require fixing.
Last Stand: For a brief period, as the player goes from standing to Last Stand, he/she is invulnerable. That needs to stop.
Martyrdom: With FF on, martyrdom can be devastating to a team if all of the members happen to crowd around the person who died, such as if they're in a room about to storm another one.
Both: They happen every time, with some exceptions for Last Stand. That should end. Reducing the reliability of these event occurring preserves some realism while making them less of a headache for other players, friend or foe.
