If the design was on purpose, then their target audience was "The lowest common denominator", which is considered by most PC gamers to be a symptom of consolitus.
How exactly do those things appeal to the lowest common denominator?
Nobody likes recycled dungeons, lack of environmental variety, half-assed sidequests or enemies spawning out of thin air. These weren't choices made to appeal to casual gamers or any gamer, for that matter. They were made because the game had a short dev cycle and the devs had to focus on some aspects of the game more than others. Dungeons and environmental variety obviously got the short end of the stick. As for the predefined protagonist, that can also be traced back to the short dev cycle. If the player could choose their own race, artists would have to make six versions (male/female human, elf and dwarf) of every piece of armor. They'd also have to record six versions of every line of player dialogue.
That said, I do agree that DA2 is a disappointing sequel in almost every regard. I don't think I like any of the design change they've made. Hopefully the next game will have a much longer dev cycle and will be much more like the original.