I think you are right in that it shouldn't dump all your power when you die. I think I will rework it to where when you get extra runes that you get a kind of buffer against death and each death only takes one of them away. That should make it so it doesn't feel bad to die.
I'll look into making it so you just take damage from falling into pits, (Or maybe it takes a rune instead with the implication being you 'teleport back up' at the cost of one) but it's definitely extra to code yes. I'll work on a more immediate solution for the current builds to have the extra buffers in the meantime since that won't be nearly as hard to do.
Edit: I think I will make it specifically so that falling into a pit will take away one symbol, but death as usual will take them all away and then make the player teleport back up to where they fell.