Sneakiness skill is useless?

[Lord Estraven]

I've noticed that, no matter how many points I dump into my assassin's Sneakiness skill, his Perception score never seems to rise above "fair" (in slug-like exploration mode, with -10 speed). Now, I realize I'm supposed to detect, detect, and detect some more, but it seems to be that an assassin really ought to be able to spot traps just walking about, especially at high levels. Maybe this is a bug? If it's intended behavior it's certainly a bit strange.

[Lord Estraven]

Okay it seems that Searching scales at 35 points per 50 points of skill and Perception only 25. That's ridiculous. 150 as for Magic Device seems to work pretty well.