1. Very preachy.
2. Run-on sentences.
3. Excessive use of arcane terminology.
4. Continuity problems - stories jump all over the place, chapters do not even attempt to flow into each other.
5. Sometimes it feels like they're just making shit up because they think it sounds cool.
6. Lack of bibliographic documentation and footnoting.
7. Extremely weak plot development.
8. Too many characters.
9. The bad guys never manage to shoot Jesus, even when there are like thirty of them standing in the same room firing at him with huge shotguns, but, somehow, Jesus can pick off anyone with his trusty revolver even if he's racing full-bore on his horse and shooting back over his shoulder without looking.
10. Characters painted without nuance. Either good or evil, not very realistic.
11. No dinosaurs or robots.
12. Flagrant overuse of predictable deus ex machina plot device.
13. Miracles are usually just a little too convenient to be believable.
14. Feels horribly biblical.