I'm sure by now most people reading this have seen the relative wealth of new footage. I've noticed a few topics voicing concern over the new power armor, and I think I've put together a rough idea of two it will play.
If you've seen the brief bit of gameplay from the mission using power armor to clear out some raiders and deathclaws, you may have noticed that it was done at a low level. My guess is that the mission is indeed available close to the start of the game as a sort of power trip intro. This is a relatively common technique used in games to give the player a preview of the power they will later possess. I hypothesize that taht mission involves finding a pwoer supply for a dead set of armor, then using it to clear the raiders, then fighting the deathclaw in it. By the end the deathclaw damages and tears apart the armor, leaving just the chassis for our player to keep.
I figure that, throughout the game, we will then set to scavenging pieces of other power armor too build our own around that chassis. Functionally, it seems to operate like a vehicle. There are several readouts along the bottom when the player is using power armor. They include a piece by piece damage display, HP% (probably overall health of the suit, though it could be for the person within), rads (obvious), the compass, AP% (action points), ammo capacity, and then 'Core' and 'Spot'. The last two are the mystery ones. Core would seem to indicate that the suit's fission core has some sore of limited fuel. The dial around it runs from 0 to 100, like the other percentage dials, but it also has a direct number readout, in the case of the video it says 11. Still guessing here, but I propose that the player can carry multiple energy cells for the core to run off of. That would be the 11. The percentage dial would be to show the power of each cell as it drains. More than likely different power armor parts will change how fast the power drains.
All of this together makes the armor much more like a vehicle, and more like the massive, bulky, robotic stuff seen in the originals. However, it will also restrict how often and how much the user can implement it. If power armor does indeed work this way there may be a way to get it airlifted to you, or perhaps using the airlift or fast travel does not use energy.
One other point that I've noticed is in the crafting video. When swapping out power armor parts in can be seen the helmets have attachment slots. Most were empty, but several had a slot filled with 'Headlamp.' This implies two things, one, that the power armor may be able to support things like night or thermal vision, and two, that flashlights in general may now be a standard beam rather than the area light that the pip-light casts. If that is the case there may be several other weapon and helmet attachments, along with other lighting options. I think this will do wonders for the atmosphere in areas that are intended to have a more horror focused atmosphere. Still hoping for road flares to come back.
Anyway, those are my thoughts, I guess we'll see how close I hit.
tldr, power armor may be a vehicle that uses fuel and you can put different attachments on the helmet