I think it depends on the game, eg. CoD 4 is an arcade game with small-sized maps which caters mostly to kiddie players and those of a lower skill rating (my boss plays it, and he is one of the least capable people I have had the misfortune to meet,) hence the high number of campers, respawns, killcams and perks. For those who prefer to run and gun, the killcam is useful but not really needed as their skills tend to be higher than those who feel the need to hide in order to get kills; overall though, fast and skilled players are punished for being skilled and playing aggressively (Last Stand, Martyrdom, etc.) but again, it's an arcade game - killcams and respawns are acceptable and reasonable.
For the likes of Arma, and even Joint Ops, those are large warfare simulation type games which require more tactics and killcams would be completely unreasonable for such games but respawns, because of the huge maps with limited numbers of players is, imo, acceptable (although JO could have upto 150 players, which was cool.)
My favourite online game of all time was Raven Shield (and Rogue Spear) which had no respawns and no killcams. The lack of respawns in such little maps made it feel far more aggressive and exciting - the fact that one hit could kill and would definitely wound, therefore slowing you down and ruining your ability to aim as accurately, made the game much more merciless than currently available games. Also because of its CQB nature, there was no need for a killcam, as most of the time you were face to face with who killed you. There were still a lot of campers, but over the years I have come to accept that that will always be a problem in small map based games.