Seriously: what exactly? Is it challenging? Does it have a good, or at least well told, story? Good, or at least interesting, characters? What?
You could do a lot of stuff, yes. But to me, that falls under "world", and yes, that aspect was great. In all Elder Scrolls games.
Become head of the Campanions.
Arch Mage of the College
Head of the Dark Brotherhood
Thane of the various cities
Build your own house
Decorate various houses
Craft within three fields and quest to obtain the items required
Free form role play and be the character you want to be.
In many ways, the Elder Scroll games are computerized DMs who are able to offer the game you want to see.
DA offered none of those things. I am still suspicious of this "memorable characters" talk. Other than saying the chick from Farscape or that british guy from Crossing Jordan, what was memorable in the least about the characters? The utterly canned Obi Wan guy who recruits you? The guy who does a Darth Vader redemption at the end? In every case it is either completely obvious, stereotyped fantasy or drawn almost completely from another, better, Bioware game.