Ah interesting! It's fun to hear what your thoughts are while playing, it's something I didn't necessarily consider when making the abilities/layout and all. In fact, thieves have an automatic see-hidden ability built into them, you just didn't run across any other than the Jewel dagger and the Cave lizards being visible (if you don't have see-hidden or the thief class, you wouldn't see them).
But yeah this is nice, and hope you enjoy the rest of the game too!