1. They are so buggy its not even clear what exactly happened except from knowing what guns they used and where they were when they killed you.
2. If i remember correctly I remember reading somewhere that Killcams sap up abit of the Hosts bandwidth, and removing Killcams would free up abit more and may help with hit detction and connection issues.
Sign here if you think killcams aren't worth the compromise.
UPDATE:
The two main reasons people watch killcams are.
1: What gun was used to kill them.
2. Where their killer was when they were killed.
You do not need a killcam to relay these two pieces of information to the player.
BFBC2's system of a third person camera on the killer and the weapon he used to kill you with being indicated has no effect on the Hosts bandwidth and is a worthy option.
Another possible option is Halos system, Where when you die your thrid person camera automatically "looks" at where your killer was when he killed you although if its bullet penetration kills or long range kills this may proove not so useful.