Re: OOC
I just looked up OD&D, it's actually easier than I remember - most traps only spring on a 1-2 on d6. Of course there's no specifics for using 10' poles, but they're supposed to help somehow (probably through role-playing tapping around trying to find pits etc.) Thieves get to use swords and listen at doors, and climbing walls. However they don't have some special way of finding traps or any bonuses to do so, and and can only remove small ones like those that would be on a chest. Thieves' abilities start out pretty poor and get slowly better too (one thing I've never cared for.) Very different from Dungeon Robber.
I don't really want to make them immune to traps at 1st level with wis and a 10' pole, Possibly make it +1 save vs. traps per level from thief, though that's pretty weak to begin with still.
Another way would be to make it d6, but you can't ever get below a 1. Or instead you bump the die up each bonus, so with +3 (thief, wis, 10' pole) it'd be 1 in 8? That might be annoying to track and explain, but I'm willing to give it a try - so I'll make that the HR for the moment.