Unlike DA2 or ME3 which were obviously rushed, DA:O had plenty of time in the oven. The problem with it was that at multiple levels the game ended up being just boring and kind of a chore to complete. No wonder that as of 2012 it had the lowest completion rate of modern BioWare games.
It wasn't just some mistakes like forcing the player to slog through far too many repetitive trash mobs or tedious levels like The Fade or infamous Deep Roads (baffling that these would be in a game intended for multiple playthroughs).
The main story was crushingly unoriginal (an ancient evil is overrunning the land...actually **** this, let them) and followed the same old BioWare narrative structure. It felt so generic and tired, a collection of obviously borrowed tropes and ideas in an over-saturated genre. The setting wasn't any better. For some reason the combat speed was set at a snail's pace and also had severe balance issues. Even the muddy art style and dated graphics conspire to bore you. BioWare associated "epic" with "long," and the game just refused to end when it would have been a better experience with tighter pacing and less filler content.
Really the best thing it brought to the table were the Origin stories but they needed more reactivity down the line.
Also the idea that DA:O was "its own thing" seems a little odd when such an easy criticism against the game can be that it lacks identity. The writing is such an obvious slurry of popular fantasy and the game itself has clear influences like FFXII and MMOs.
I'm being harsh here but I don't consider DA:O to be an ideal that should be aspired to. Why aim for blatant mediocrity?
Anyways the biggest reason you're not going to get a game that plays like DA:O is that it was a PC game through and through (which was clumsily ported to consoles) and BioWare along with everyone else that makes AAA multiplats has long ago switched to having consoles be the lead platform. Instead of people pining for something that isn't coming back, they should either spare themselves further misery and move on perhaps to something like Pillars of Eternity or accept the new paradigm and offer suggestions on how to make a better game within it.