Nobody trains ALL their senses. In every single way they use them. They just don't.
Does a master wine taster have superior hearing because they've trained themselves to pick out particular flavors? Not in the least.
Irrelevant. We're talking about survival skill and investigative training. In those situations you train eyes, ears, and methodology or you
aren't trained. Paying attention to touch, taste, and smell can be nice too, but they aren't the focal points.
Does someone who has superior long distance eyesight and who can pick out details that others can't
That's not a
skill, that's a
physical ability. As noted, specific physical abilities like "keen ears," "sharp eyes," or whatever are perfectly fine attributes to have alongside skill training. You can't skill-train away being hard of hearing, nearsighted, not-an-elf or whatever.
But as soon as you put all of these things together into a single skill called "Perception"... a skill that a good 50% of the party will probably end up having... you now suddenly have a party full of Daredevils.
Daredevil is a superhero. He's isn't what he is because he's particularly
skilled at those things (though it helps).
The situation is much more analogous to front-line soldiers dealing with things like ambushes and booby-traps. Either someone gets good at spotting warning signs or you get dead quickly. Very few groups have someone who "trains to listen" while someone else "trains to look" and someone "trains to scrutinize" - that's just ridiculous. You're either developing the skill to observe and scrutinize your environment with your eyes, ears, and mind under a particular set of circumstances or you aren't.
I'd much rather have "Danger Sense" or "Alertness" as a skill, which tell us the person was specifically trained in spotting ambushes. And only ambushes. No bonus in addition for finding secret doors, or finding someone hiding behind a wall during combat, or noticing the historical details painted in a tapestry, or anything like that.
I agree with the general principle, if not the specifics.
"Alertness" should jolly well help you notice someone hiding during combat, as well as identify traps and other hazards. A
skill is not Spidey Sense - it is a completely mundane phenomenon. You notice things are out of place, that people are hiding, that objects have been disturbed, that birds stopped singing, that women and children are conspicuously absent from the street, or that everyone is constantly giving you sideways glances when they think you can't see them.
No, it probably doesn't alert you to things like whether or not that Mona Lisa is a forgery.
I can see a firm distinction between Investigation and Awareness, or even some broader skills that encompass situational awareness. There's no need to be so narrow that two characters couldn't confront the same problem using two different attributes, and there's no reason two different skills couldn't apply to the same problem either. Exclusive silos (monster X only goes under skill Y, searching the room is only skill Z) are unnecessary.
I'd much rather see a skill list like "Alertness," "Investigation," "Low Society," "Polite Society," "Commerce," than "Spot," "Listen," "Search," "Diplomacy," "Bluff," "Use Rope," etc.
- Marty Lund