I've been playing as a sort of Artificer lately and tinkering around with traps is a blast. Literally!
But I've felt that it would be cool to have even more traps to pick from; some already exist in the module, such as traps that apply dispels/breaches, blade barriers, clouds etc. - however, they cannot be recovered and are not playable at all as far as I know.
Something that might add a very cool touch: Add magical traps that can be crafted via Use Trap, but that also require a Spellcraft / Use Magic Device / Lore check to make, with more complex recipes possibly involving scrolls, wands, potions or what not.