HandyBuddy, i agree with you that 70 ms is not much slower than 0 ms. But, what if that very very short amount of time was the difference between living and dying? wouldn't be too fun to play a co-op game and miss shooting something by a hair, or to have a Hunter in front of you, and then half a second later you're about 2x farther away from you then he was due to a lag spike.
Wow... I didn't realise that other games had co-op too... maybe I should try them out as well.
Anyway... I decided to email Gearbox Software about this, and got a reply from Randy Pitchford:
"We are working on adding a networked coop feature, but we cannot predict when it will be complete or if it will meet our quality expectations enough to be released."