ToME WikiDerakon: I'd like to see some general changes to how enemies see the player:
1) Give some (most?) enemies infravision, allowing them to see players who are invisible.
2) Make enemies unable to see the player if he is not standing on a lit square and is out of infravision range.
3) Alert enemies can roughly track the position of players with poor stealth, but not get an exact fix.
4) Smart enemies should know that the player is somewhere near his light source. Ditto on the non-exact fix.
4a) (related, but not really a monster idea) Have lightsources that create "invisible light" which only the player can see, thus countering the above.
5) If the player attacks enemies via melee, then they should know where he was last turn and be able to retaliate with greater accuracy. If the player casts sourced spells (bolt/ball/beam/area, but not LOS or targetted "unsourced" spells like Shake and Stone Prison) then smart enemies should trace them back and have a general idea of where the player is (similarly to an invisible player carrying a light source).
And for attacking:
1) If the enemy has no clue where the player is, then it won't use attack spells (no more orcs with magically perfect arrows, please!). Smart enemies move to locations where the player's position is more certain (e.g. corridors or doorways).
2) If the enemy knows roughly where the player is, then it will favor area-effect attacks over bolt spells or melee.
3) If the enemy knows precisely where the player is, then proceed as normal.
These changes would have several consequences:
1) Stealth becomes an issue even after enemies have awakened. A stealthy character could "put out" his light source (or just carry an "invisible lantern") and retain the element of surprise.
2) Invisibility as a player flag stops being so bloody annoying for melee-oriented players. A room full of awakened orcs has almost zero melee capability but impressively ridiculous missile capability, while it really should have the reverse.
3) Enemies in general will react more realistically to an unseen threat.