My theory (I’ve mentioned before) is that there’s no way we’re going right to the Arctic. The advisers themselves are at White Forest at the end of EP2, and I’d bet anything that they brought some more backup- probably all they could get. So there will be some fighting at WF. My guess is that Gordon will wake up a minute later, maybe in another room. Barney, Alyx, Kliner, and Magnusson are there. Everyone’s preparing to leave; the plan is to meet up at a small rebel base further up north we haven’t seen yet. A short conversation will take place about that, and Barney + the doctors will separate from you and Alyx. The northern base will be what Black Mesa East was to HL2, but the trip will be shorter.
Anyone who expects HL3 to get to the Arctic quickly is mistaken. At least the first two or three chapters will involve getting away from WF to a safer location. Then they will journey to the Arctic and see the Borealis. I can only hope HL3 will be a long game. The majority of the game can’t be the journey to the arctic, but the journey can’t be really short. It should take an hour, maybe.
Once we get to the Borealis, who knows what. That’s the event horizon when it comes to predictions. We just don’t know enough- maybe Valve still doesn’t know themselves (I hope they do)! Maybe we’ll get a third new innovative weapon from the Borealis alongside the unknown powerful AS technology. It won’t be the ASHPD; Aperture must have made more than one kind of handheld device in their gigantic underground facility.
All the theories I see about HL3 are so quick to jump right to Arctic territory. Why? Consider all the time in HL you spend just getting from place to place. We’ll see such travel in HL3, and some important things are bound to happen along the way.
As for things like the Combine homeworld, I’m hesitant to say it’s going to happen in HL3- maybe we’ll get there, but sneaking around the homeworld of a huge evil multidimensional empire with whole planets full of resources and advanced technology stolen from who-knows-how-many races is a bit harder than infiltrating just one Citadel.
Maybe at the end of the game Gordon can steal a gigantic can of alien insecticide to get rid of the Xen wildlife on Earth. It would be huge and oversized, like the ASPQTD, and would hold way more on the inside than outside due to Secret Combine Space Warping Janitorial Technology (SCSWJT). That will be the last chapter: at the end we get to go around effortlessly cleaning up the head-crabs, antlions, etc. Left click to spray, right click to squirt.