a Roguelike based on MZX would be awesome.
Heheh, you mentioned MZX. Awesome. I'm a member of the MZX community

Anyway, my main point is just that it needs to be easier from a user interface standpoint to fire arrows. It has to be as simple as melee attacks, otherwise a lot of people are going to use melee instead. I think autotargetting would be good, and pressing f repeatedly should fire at the currently selected target without any further input. That seems the most reasonable to me, if you want to keep the traditional rogue feeling of ranged weapons alive. Again, I do like the way it was done in MetroidRL.
Personally, I want to try having any enemies in a range be automatically attacked by your ranged weapon. This seems reasonable to me, though it's quite a move towards more MAngband style combat. But it requires absolutely no GUI changes, and the benefits of equipping a ranged weapon along with a melee weapon become quite apparent imediatly.
Maybe I'll make a demonstration case for each or something sometime.
The alternative in my mind to making it as easy as melee is to make it much more powerful than melee which would compel people to use it anyway.
Edit; Also, DoomRL did it quite well too.