Well, regardless of what you think of the quality of Arcania, the fact is it isn't a SONY property. It's the bastard child of the Gothic series which was PC exclusive. And it was also initially released on the X360. Sony just happened to get an HD remake with expansions.
I honestly grew bored with the game a couple years ago and haven't gotten too far in it, so I can't comment too much on its quality. But I can tell you that what I did play was nothing compared to what the Gothic series started out as, and what Risen has done to continue the "series".
Luckily, Piranha Bytes has the rights to the Gothic series once more, so hopefully we get a REAL Gothic 4 some time in the future.
*edit* This is what they're actually working on right now. And it looks bloody fantastic:
ELEX:
http://store.steampowered.com/app/411300/