I was worried about that too, but their game guides are great and you can learn details along side any characters you bring in. I'm totally canon-blind to Dragon Age, but it's really been easy to get involved.

It seems to be more plot than Slice of Life. But there's SoL too. And unless you sign up for specific missions within the plot, you can pick how involved or not you get. (Of course, as long as you meet AC requirements.)

Don't let my excitement for the game scare you - It's not as intense as I am LOL