Re: What about gameplay?
By far the most important point about gameplay is that this is a third person action-adventure, it is absolutely not an isometric-style tactical game like Origins. They've almost sort of pretended to give a tactical view, but on the PC at least it's completely broken to the point of being unplayable. The rest of the game is a pretty decent port; some of the interfaces are obviously designed more for a controller than a mouse, but everything works fine. The tactical view, on the other hand, starts off by slapping a giant glowing, and entirely unremovable, crosshair in the middle of your screen to show where your controller is aiming, apparently completely forgetting that a mouse is a thing at all. The view is zoomed in to the top of your character's head and cannot be zoomed out further, meaning you need to use third person mode to actually see anything, the camera controls are virtually non-existent, and you can't give group orders or actually select anything; it's basically just third person mode with a broken camera.
On the plus side, as a third person game that lets you control and swap between a group, it's great. But if you liked DA:O and want another game like that, you're sadly out of luck. It's more tactical than most - you can still pause to give orders, positioning matters more than ever since not only can thieves still flank and backstab, but shields only protect from the front and are far more effective than before when used properly. The lack of healing allows more party options (no more mandatory Wynne), and also requires deciding when to press on with exploring and when to head back to base (with fast travel, so not too much mindless trudging around) - and enemies respawn, so if you're too low level for an area you can't just grind away and slowly wear your way through.
There's sadly less customisation. Characters aren't locked into unique equipment only for them (other than Varrick and his crossbow), but almost all weapons and armour are locked to a specific class; no more mages running around with swords in heavy armour. On the other hand, there seems to be no actual difference between light, medium and heavy armour anyway; they all have basically the same armour values and differ only on the bonuses they get. Seems a bit of a wasted opportunity really.
I haven't played Assassin's Creed or Far Cry, but you do a lot more than just capture forts. Indeed, I've put a good few hours into the game and haven't even found one so far. Power and influence are gained by doing the sort of things you'd pretty much expect - establishing camps and spreading the Inquisition's influence, helping out refugees with food and defence, and so on. It may not be the most original mechanic, but it fits in very well with both story and gameplay - you're not just running random errands for nameless NPCs as in so many RPGs (including DA:O), almost everything you do is something it actually makes sense for your character to be doing.
Overall, this is basically what Dragon Age 2 should have been. The world is more open and expansive than DA:O, and looks a hell of a lot better even on a fairly old PC (I'm still running a pair of GTX470s and have most settings on high, although I did have to drop the resolution down to 1920x1200). I'm not far into the story so I can't say how good it is throughout, but it's at least somewhat less generic than DA:O's "totally-not-orcs are attacking, sort it out". The templar vs. mage conflict is well fleshed out, with everyone involved having legitimate points and no-one simply being evil for the sake of it; even those who appear so at first tend to get shown from a more sympathetic point of view at some point. From what I've seen so far, the writing is mostly of much better quality than recent Bioware efforts.
On the Origin (EA, not DA) end of things, you do have to install it and the game runs through it, but after activation you can put it in offline mode and do not need a permanent internet connection to play. Also note that the game comes on 4 DVDs, and takes about half an hour to install from them. It's just like being back in the '90s again! If you have a decent internet connection, it may well be faster to just download it through Origin even if you have the discs.
If you don't like third person games, you won't like this because that's what it is. But if the idea of a more tactical than usual third person action game appeals, this is certainly one of the best around.