If Dragon Age were to have a more complex ruleset it would require either a extremely good manual or tutorial or both. For example earlier Bioware games based on the D & D ruleset had very large manuals because it not only had to explain the game but also the D & D ruleset. Example the manual for BG2 is 264 pages long. The first 46 pages are used to expalin the game the other 218 pages explain the setting and the D & D ruleset along with descriptions of all the spells used.
Neverwinter Nights has a 218 page manual. The first 37 pages explain the game. Pages 38-156 explain the D & D ruleset. Pages 157-172 the toolkit. Pages 173-218 ate the appendices with charts and tables plus the index. Neverwinter Nights also has an in-game tutorial.
Without a very good manual or tutorial I speculate that the average casual player would probably look elsewhere to spend their entertainment dollar.
That is one of the reasons that games like Dark Souls, Demon Souls, (other upcoming games like Wasteland 2, Project Eternity) and older games like Wizardry, Ultima, Might and Magic or Bard's Tale now find a home in a niche within a niche market.
Since Bioware/EA is in the entertainment business it is not just fighting against other game companies. It is fighting against most if not all entertainment products which include movies, books, sports etc. There has to be a compelling reason for purchaser of the game to choose it over other entertainment products, because the person is going to invest both time and money.
Now, some may say well play the game on easy. That still requires that the purchaser invest time to learn a more complex system which requires a good manual, tutorial or both.
I like complex systems that allow me to really define my character, but that is not everyone's cup of tea. The rule set I would like to see many on this forum would call tedious.
I can pick up a book (like the Hunger games) and simply start reading. I can go watch a movie or sports contest (as many do). I can go out and enjoy fine dining. What is going to compell that same person to pick up a game like Dragon Age?
Many of the most enduring games have a simple ruleset, but the depth of play is where the complexity come in. For example , Scrabble, Chess, Monopoly, Othello, Xiangqi or Go have simple rulesets but actually mastering the games is a different story.
The developer of crpgs has to strike that fine balance so that complexity does not equal less fun and tedium.