Here is the primary difference between the Baldur’s Gate series and the Dragon Age series:
Most people quit Baldur’s Gate after 20 minutes, when they are killed by wolves after walking out the front gate. Baldur’s Gate used the full range of game mechanics to build a world, and that included making your first death nearly inevitable as a learning experience. The people who quit Dragon Age did so because the prologue never ends.
Here’s why that primary difference is so important to Baldur’s Gate: after bandying about in the world for a significant period of time, growing stronger and gaining party members, you might encounter some of the wolves who gave you Death #1 (or Near-Death #1)--and you beat the shit out of them in seconds. They're not a threat anymore. Your growth is clear and evident. Is the conquering-what-once-conquered-you method primitive in terms of emotional engagement? Sure! It's a method using the narrative of games; “you died, try again” (aka losing) is the most familiar element of a game, and Baldur’s Gate is sure to teach you this lesson early. Is this mechanic user-friendly? Not as implemented, although low-level D&D is a crapshoot to begin with, but it's certainly possible to make death less frustrating through judicious use of auto-saves, fast reload times, and/or a "rewind" function (god bless the PSP’s Tactics Ogre for this function, by the way).
Baldur's Gate used game mechanics to 1) show you the world is a big, unfriendly place and 2) make you feel powerful after a long progression of incremental progress. Furthermore, an important part of Baldur's Gate’s expansive and hostile world is the constant reminder of being underpowered - nothing’s more demoralizing than stumbling on a Lich’s tomb and getting wiped out after a single Time Stop spell - but once you’re more powerful, you can return and wipe the Lich out and claim his useful stash of weapons and spells. It's an emotional roller coaster, which keeps you engaged in short bursts across the sixty hours it takes to complete the game.
It's also reflected within the central conflict of the plot, which is (GENTLE REMINDER THAT SPOILERS FOR A TEN-YEAR-OLD GAME ARE INCOMING. I HOPE THIS DOESN'T OFFEND YOUR DELICATE SENSIBILITIES) the revelation that the player character is one of the offspring of Baal, a God of Murder And Stuff. Which grants a shitload of Power, which the sequel’s Big Bad, Jon Irenicus, wants to corner the market on (specifically, the Murder Market, and specifically by utilizing the act of Murder, multiple times, until no competitors are left). The PC hunts down other Baalspawn, and later Jon, across multiple realms while struggling to control/go completely fucking bonkers with his own infusion of Power. So yeah, it's a D&D plot, not exactly subtle, with the expected levels of thematic density (none) and emotional resonance (marginal), and yet, the theme of "power" is constantly reinforced by both the plot and the game’s mechanics.
With Dragon Age 2, as you progress from poor disenfranchised slug to Champion of the City and engage in an open three-way power struggle with the SeriouslyRealChristianity church and the We’reNotTerroristsWe’reModerateMagicians mages, your enemies are--from the beginning of the game until the end--the same mix of ogres, darkspawn, and human/quasi-human beings. Who look exactly identical. And take nearly the same amount of time to kill.
I would love to say that Dragon Age 2's plots are about the Futility of War, but unfortunately while DA2 is a bold move away from The Bioware Plot, it is Not A Plot. It's a series of vignettes that tie in with each other, but not necessarily with the player's emotional state while playing the game or with the combat mechanics (i.e., using magic in front of Templars has no in-game consequences, compared to BG 2 where the use of magic in-city got you Effed Up right quick). Progression means something that gets you the next cutscene, not something that makes you feel like you’re systematically mastering combat.
I think it says a lot that DA2’s only skill check comes in the form of locked chests, whose contents are hilariously worthless--because giving powerful items to the small subset of players who can pass the skill check might mean the game isn't balanced! You might become too efficient at killing ogres and darkspawn, and the facade would crumble.
TL;DR: In Baldur's Gate, when you first encounter wolves, they will kill you and you will have to reload from a save that you almost certainly didn't make. When you see wolves later, you kill them mega-fast and feel great. In Dragon Age 2, when you first encounter an ogre, it kills your sibling in a cut-scene and then you kill it. When you see ogres half a dozen times later, it takes the same exact amount of time to kill it--every time.