But that's getting too complicated for the style.
This is the point. As I mentioned elsethread, DRLINA :P
I don't think we want an overcomplicated RL, there are lots of these already. Take a look at Dwarf Fortress, Pelleron's Brilliant Rebirth, Adom, etc. What makes DoomRL stand out before other RLs is its unique style and its simplicity. If things like different types of damage, ultracomplicated traits, 30 million weapons and so on, we'll just end up getting a 10 hours a game RL like the others.
I really wouldn't want DoomRL to become that way.
About the other subject, good AI is always cool. But I would go the F.E.A.R. approach, where enemies (even in lowest difficulty settings) are as smart as they can be, and the difficulty just changes how many are of them, how much damage they deal to you and how much damage you deal to them.
I don't think playing HNTR or ITYTD should make them be more stupid.