I think it should be so that the more obvious a trap is the more dangerous it is, even to the point of instantly killing you. The Ayleid slabs and spiketraps are grossly obvious - all you need to do is slow down a little and you
will notice them - and should kill you instantly. Poison traps and poison emitters are not that obvious, but due to the nature of poison, you still have a chance of healing yourself, but these to should be more dangerous.
Dropping flails on a pressure plate or highly visible string, shouldn't be dangerous wrt damage, but it should raise an alarm instead which could prove very dangerous.
I now play a Breton Mage at 75% difficulty (no trap mods, currently lvl 45), and I've played so much I only speed play this character. Although he takes a good amount of damage from certain traps, I just tend to ignore them and walk into them - hail magicka regen making life oh so easy