Right. That's what makes me call wop on the whole thing. I think Bungie is just biding their time until a major co-op announcement. They probably wanted us to know about the Arbiter being playable as the second character, but they weren't ready to announce the co-op megaton yet, so they're playing up that jazz about the warp problems. It may be an issue, but like you said, if they're doing splitscreen and especially system link, then they've already solved it, to an extent. They're just buying time, so they can drop a nuke a little closer to release.
I think about the stuff we already know about - multiplayer options, Forge, armour permutations - and it scares me to think about the stuff they haven't told us about, yet. There's still two months til it releases - they have many more things to announce, I'm sure.
They confirmed system link in the mag.