If I had the time and the will to cause myself self-harm I would replay and DA2 and ME3 in a single week, jot down some notes about the two games, then make predictions based off that.
I don't expect this game to play even close to DA:O. It's going to be a mishmash of ME3 and DA2 and I'm almost certain we will see similar plot points from those two games. We've already seen assets from DA2 and DA:O being re-used in DA3. Generally, I would applaud developers for being frugal (I'd much prefer better gameplay and story than extra money wasted re-inventing the wheel by recreating the same damn assets over and over), but it nevertheless irritates me for a reason I can't yet place.
You can be certain all of the bosses will be high fantasy, dragon ball z style. Darkspawn this, demon that. I can't even recall a Dragon Age boss that wasn't over the top and immersion-breaking -- like I wasn't in a WoW raid of some type. Would it kill you guys to engineer interesting encounters with average humans? With all the pointless flipping around and exaggerated staff flinging, it's utterly obvious not an ounce of the game's combat will be tactical, nor even plausible -- understandable. I like games that aren't afraid to take me into the thick of battle, it's what sets games apart from movies, who often try to make combat a ridiculous and incomprehensible spectacle. Good games make combat pretty, but they put a greater emphasis on simulating the results of your key input, making it feel more like you're in control of the action. So far, DA3 looks like you press a buton and awesome happens -- only, awesome just becomes confusing after a while.
Maybe it's just me, but compare LoL and DotA. Sure, DotA has some problems, but I literally cannot play League of Legends when the end game shows up. There is so much light and particle effects and movement I literally see a blur of color during a 5v5 fight and I physically just lock up and can't figure anything out; I'm in a daze. Dragon Age 2 kind of did this as well, it was hard for me to get the positioning right, what with the awful camera, and all the stupid awesome everywhere.