The current speculation is that they'll be costed around 10-13 points, which puts them in the realm of the marquee heavy jacks and beasts out there... If the Khador Gun Carriage is just a couple big guns and a burly impact attack from a charge, I'd expect it to fall short of a model like Beast-09 in terms of awesomeness.
At this point, I'm starting to frame my speculation somewhat, and I'm ready to say that it looks like the War Engines are all focused around ranged/support tech; With the exception of the Wraith Engine (or whatever the Cryx one is called), none of them look like they're supposed to be charging anything. I suspect this is intentional; without a raft of special rules that diverge from the entirety of the current movement and model placement rules, there's just no way something on a base the size of a CD is going to make it to close combat in any meaningful way. Even with Bulldoze, it's really hard for even a large-based model to shoehorn it's way into combat through a lot of other models.
Here's my call, based on the conjecture out there now: either 1. War Engines get some rule like Ponderous or Juggernaut or something like that that allows them to displace other models (potentially only small and medium based models, but could be all models), or 2. War Engines are primarily ranged and support pieces that act as mobile command posts and the Wraith Engine gets Ghostly.