Give a few listens. I listened to the free iTunes stream a few times in the past week before I picked up the CD this morning. My first impressions were like yours, but it really "clicked" for me as I was listening during my commute this morning.
Overall, I think Tony's riffing is stronger here than on The Devil You Know. Also, there are similarities to previous Sabbath songs all over the album, and I believe it's intentional. This is intended as a valedictory effort by them, so they're consciously referring to the past.
That Planet Caravan rip-off is actually way better than the original song.
The mastering sucks with the brickwalling, but the recording quality is considerably better than The Devil You Know. Everything seems crisper and more well-defined, and that's the best bass sound I've heard from Geezer in many years. I wish the drums on The Devil You Know sounded like this, but then Vinny Appice has always favored that dull, thuddy sound for some reason.
Oh, and Bohmer, "God Is Dead" might be the worst track on the album. I'm not sure why they released it as the single.