Mordenheim does look interesting (I was/am a big fan of XCOM). I'm eagerly awaiting the full release.
As for the 40K MMO, I'm very interested, but also somewhat skeptical. I almost never like what they do with MMO games, so we'll see. If I played, I'd almost certainly play Space Marines, though. I've always preferred a sense of balanced offense/defense to specialization in shooting games.