Aether said:
If I wanted 1hk's I would go play a sniper in CoD or Halo. But if you have a large mechanical suit of armor, it's expected that you can take a few hits. A big selling point of the game is actually being able to control a mech (walking around, hopping, shooting, evading), not spawning and dieing instantly from 1hk sniper weapons. Also, if you consider the Armored Core series, which we all know is the main game of the genre, they do have 1hk weapons (the charged Kojima cannons) but they are near impossible to use. And if they were any easier to use, everyone says they would be game breaking.
That is not to say that 1hk is never fun. I used to play some instagib in quake derivatives and that was very fun. It is purely optional though.
Yes, this was one of my biggest problems when I played BF2142, you would get spawn kill and take 15 seconds to respawn. And from the video, it also looks like there will be a 15 second respawn, which I'm fine with so long as it takes a little bit to take you down.