I'm all for a story mode, and to be honest I kinda liked bits and pieces of Flyings Steel's idea. It was very intriguing in the beginning (although Half-Life did pop up in my mind

) and interesting. However, when they entered the portal and was on the other side, that part didn't much compel to me. It would need a bit different approach I believe, cause as it stands now, that would be deathmatch and other type modes in the campaign (not necessarily but still not appealing to me much

). I'm not much for different game modes for a campaign, I was thinking of more genuine campaign, like Prey, Half-Life (2) etc. meaning, when you die, you die, you don't respawn.
@Fisume:
We could still keep the original campaign and you'd never have to play the storyline or even take it into consideration. I think it's fun that it exists for those who want it, but does who do not can choose a different one in their mind or ignore it altogether.