Split screen co-op requires more horsepower as two different renderings are required. Even with the drop in resolution, etc. it normally requires more power.
Few, if any sandbox games have or are likely to have it, for current HD consoles.
What's interesting is their comments confirm KZ2 is heavily streaming defendant, to levels in line with a sandbox game rather than a level by level FPS game. I'll be curious to see if this was to allow for very detailed levels, or larger play areas that are less 'level' orientated than your average FPS.
Either way if graphics/detail levels/particle effects continue to go up for PS3/360 then its likely we'll see more and more games drop split screen co-op in favour of online only.
Personally, I prefer online co-op as I don't like looking at a much smaller screen area.
Final note - I don't see this as flamebait for 360 more powerful than PS3 nonsense posts. Both have plenty of games with co-op and good graphics, KZ2 developers have taken what appears to be a slightly different approach with a higher level of streaming and that's what's behind this, not a lack of comparable power in the PS3.
Try to be reasonable... its easier than you think...
