- Rules for naval combat (Sea of Blood is my favorite so far, but there is still a lot of room for improvement.)
- Mass combat rules (I liked the old-school War Machine system best...something similar would be right up my alley.)
- Vehicle combat (chariots especially, but also airships and war wagons.)
- Better, more straightforward rules for divine ranks, divine powers, and other godly stuff.
- Gunpowder (cannons, muskets, and other pirate-related firepower would be awesome.)
- Better (more random) treasure generation. (In fact, an overall reduction in the amount of "cookie cutter" rules would be awesome, IMHO. Call me old and busted, but I don't like this new hotness of standardized stats, hp, xp, $, etc.)
- and this one from my wife: "Faeries. Why are the kings and queens of the Fey type missing from the core rules? Am I the only one who noticed? I want faeries in my fourth edition."