In my opinion, non-linear does not necessarily equal exploration. You don't need a sandbox to explore.

Of course, DA:O is mostly hubs you travel through with a few zones, but those do give me the feeling of wonder you get when running into something unexpected such as in BG.
Oh well, I guess I just have to gush about how much fun I'm having.

I lose attention quickly, so I need all the motivation I can to keep playing.